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I have developed ZnO thin film in nano rod structure on glass substrate and have calculated the absorption coefficient (α) value from absorbance value. I also have plotted ln(α) vs. photon energy (hv) curve. Now I want to calculate Urbach energy from the curve but I donot know the calculation procedure. Please help me by providing calculation procedure. Here I attach the xls file.
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Expansion of SU in SU-8 Photoresist?
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SU-8 Photoresist
By: Frederik Ceyssens and Robert Puers
SU-8
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As part of a project team, we are attempting to set up experiments that require the creation of a thin film of either chitin or chitosan. Any known methods that would be cheap and within specs? 
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Hi Rayon
You can try the solvent casting method also, as it is very economic. Addition of Clay or plasticizer in that may give the better result.
Regards
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Quantum materials
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You may ask:
What is the quantum effects on thin film?
I think, for thickness less than 10nm quantum effects dominant, and a researcher should look at the properties and phenomena in a quantum mechanical perspective.
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Tell me in a meticulous way with reference papers. Optical and Electrical conductivity.
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The main difference is that the electric conductivity is for a static field, i.e. it has a specific direction and a specific time independent value. Electrical conductivity is the measure of a material's ability to allow the transport of an electric charge. But the optical conductivity is a time dependent value. Light has an electric field component that varies in amplitude and direction over time, and that is why it is called optical conductivity. The optical conductivity arises under optical excitation without the presence of applied electrical field. Such conductivity appears in result of the presence of the gradient in concentration of carriers in different regions of semiconductor material. Thus the optical conductivity is caused with the diffusion current in the material. The value of optical conductivity depends on the power of the excited light. The optical conductivity is also closely related to the dielectric function, the generalization of the dielectric constant to arbitrary frequencies.

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On glass substrate.
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Actually i am working on thin film of nickel oxides
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Hello everyone, 
I am fabricating ZnO based bottom gate top contact thin film transistor on Si/SiO2 as substrate. Thin layer of zinc oxide(ZnO) has been grown on substrate by RF sputtering. Finally source/ drain contact of aluminium (Al) has been deposited by thermal evaporation using shadow mask. Thickness of the SiO2  is 300nm, however a significant gate current (in the range of uA)  has been flowing between bottom gate (Si) and top contact (Al). 
How can I reduce the gate leakage current?
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The gate leakage current can be expressed by the simple expression I= JA, where J is the leakage current density and A is the leakage current area.
So, to reduce the I you have to reduce both to the minimum possible value.
In addition you may have short circuit by contacting ZnO to the silicon substrate. This can happen if your deposited ZnO overlaps your silicon dioxide isolating layer.
The key word is to use Mesa structures.
Best wishes
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I am fabricating metal oxide TFT on SiO2(300nm)/Si(p++) substrate. In output characteristics I am observing minor linear modulation of Ids with change in Vgs but unable to get Ids saturation for as-deposited samples and linear modulation improves after air annealing. I also tried active layer of different thickness and vacuum annealed the samples still no saturation was found.
There was no gate current leakage in device.
Note:
Structure: inverted staggered; W/L= 2000/100 um
Reactive dc magnetron sputtering for active layer deposition; S&D= Ag (thermal deposition)
Characterization: Keithley 4200 SCS
Attached below are O/P and Transfer Characteristics of samples after Air annealing
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I meant the sheet resistance (Rs) taken from the slope of the TLM curve.
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Looking for a new challange in the High Tech industry in the Eindhoven region in The Netherlands. I am interested in thin film technology e.g. surface modification, functional polymers, nanotechnology.
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anyone ?
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I have a A-cut single crystal sapphire which I want to etch. Based on literature, I tried using KoH (W/o heat and with heat). But both of these did not work. Does anybody have experience with this?
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Hi Karthic,
The standard etchant for sapphire is the mixture of H2SO4 and H3PO4. The temperature can be set between 200-270C so that the etching rate can be well controlled. But be careful: the hot mixture is very corrosive. Handle with care. For details, check my RG page for several publications on this topic.
Best,
Yang
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Prepared chitosan film by dissolving chitosan in acetic acid solution, add solution to plate mold and dry it.
How can i decrease time in "dry process" to forming film?
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I am also working on the same.I think controlled heating wold be better option.
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Hello, I am working with AFM and I need to deposit different polymers on ultra flat stripped gold chips on silicon wafer. I would like to purchase the ultra flat stripped gold from platypus
I know these chips are meant for one use only, but there is someone aware of a good cleaning procedure I could use to remove the polymer and the possible contaminations and reuse the chip more than once?
Thank you very much for your help.
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You can try to dissolve your polymer film with appropriate organic solvent and deionized water rinse with subsequently treatment in oxygen plasma. 
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I'm making a poly(lactic-co-glycolic acid) film from CH2Cl2 in a flat aluminum dish.  The film itself is fine, but sticks to the dish to the point of having to stretch and even warp the film.  
Using a flat glass or PTFE dish might help, but I haven't readily found dishes that are truly flat (e.g. petri dishes I've gotten don't have a uniformly flat enough surface).  I can't use a plastic dish that is not inert to DMSO, either.  So, does anyone have a recommended casting dish or similar that they can recommend?
Aside from trying to find out the perfect casting dish or tool, is there any other suggestion for helping to readily remove the film?  I had been thinking of casting a film of PVA first, and then just washing that out with water.  Would that or something similar be efficacious? 
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apply some paraffin oil on casting plate than wash off the film 
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I'm interested in permanently magnetizing a small piece of Ni or Fe. The size of the piece is quite small with diameter of 1 mm and thickness around 100 um - 500 um. 
What are the field strengths that would be required to permanently magnetize the piece, and what would be the simplest method of achieving those?
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Ni and Fe are generally soft magnetic materials, which can be easily magnetized. Perhaps the simplest method is to use a permanent magnet. Permanent magnets such  as neodynium iron boron or samarium cobalt magnets, would be enough powerfull.
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I have been looking for the conductivity of Cu2O and CuO thin film where thickness ranging between 100-200nm and the minimum sheet resistance is something around 7.2Kohm/cm which means electrical resistivity of the film for a 200nm film will be around 1.44x10-3(ohm-cm) which is way too low when compared with other techniques. 
Also, I could not find people showing this much low resistive in the past (or maybe I could not find a relevant paper). I wonder If someone could tell me what could be the possible reason for the decrease in the resistivity  and also if someone could share some relevant paper with similar low resistivity then that would be great!
Thanks 
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As far as I know for sheet resistance the standard unit is 'Ohm square' or 'Ohm per square'. So how do you calculate the value for the resistivity from the number you give, with unit 'kOhm per cm'?
If your calculations are correct: could it be that your film is actually metallic copper and not an oxide? Or that your film is actually much thicker? Or that it is on a conductive substrate? How did you measure sheet resistance?
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Greeting everyone,
I want to calculate spectral selectivity of my thin film for optical analysis. I already measured the reflectance (R%) but unable to do emmisivity test in due to the unavailability of emmisivity instrument at my place. Is it possible to obtain the spectral selectivity with my reflectance or absorbance data only?is there any other formula that can be used?. your knowledge is highly appreciated
thank you in advance for your help :) 
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I am not so familiar with this. I suppose you have to differentiate between reflection and reradiation of light.
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Hello,
I'm trying to synthesize mono- or bi-layer MoS2 using a CVD process. Up to now, I've never success this CVD process without promoter.
So, I'm about to use PTCDA to promote MoS2 synthesis. I could find many papers that used PTCDA as a promoter. But they didn't mention about the details how to coat PTCDA onto SiO2 substrate.
I just prepared a PTCDA solution (26mg PTCDA powder mixed in 5mL of DI water) and tried to use spin-coating method (1000rpm and 3000rpm).  But the substrate doesn't seem to be coated. The PTCDA solution was just washed out and remained a red stain as you can see at the attached picture. The red stain was an aggregation of PTCDA powder.
Can you share your method or any advice to coat PTCDA?
Thank you.
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Typically you need a good solvent to prepare spin-coat friendly solutions. Looks like PTCDA has low solubility, even in aromatic solvents, which are generally toxic and require proper safety standards to work. I'm not sure how soluble it is in DI water, it looks like it probably isn't from the powderous clump you got. You will have to utilize alternative methods to apply PTCDA. Also, what is the substrate?
Why are you using this promoter for MoS2 CVD growth? Most standard CVD methods for MoS2 on several different substrates do not require adhesion promotion. 
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We have CuS thin film with (Cu:S) molar ratio (1:1), and we got nanoplates and very distinct and clear particles on the surface. But when increase S concentration (1:2) and (1:3) for (0.1 M, 0.2 M and 0.4 M), the film surface became non-specified aggregated particles (actually there is no particles just aggregations) with porosity. Any explanation for this significant change in surface morphology?
Many thanks in advance for your help and your time
Best regards
Fayroz
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Dear Hassan Alshamsi 
Thank you for your interest, I have no problem with aggregation as much as I have problem with the structure shape. I want to explain why it change?
Many thanks with regards
Fayroz
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I need to get an idea of how thick the native oxide is on a silicon wafer (100) that is kept at room temperature. The wafer has not been treated or cleaned in anyway.
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If you would etch a silicon wafer in HF and leave it to the air the thickness will be in the order of ~20A.
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After doping CdS with manganese the d-spacing decrease from 0.270nm to 0.240nm. 
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Mn substitutes Cd in Cds lattice. The smaller Mn radius results in contraction of the lattice constant and then the decrease of d-spacing.
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I've synthesis colloidal metal nanoparticles and i need a protocol for adhesion of these metal nanoparticles on a glass substrate as it remain stable in water for several hours.
thanks
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i think its better use some binders for your metal nanoparticles such as ethyle glycol , glysoral, etc.. for strong bonding on glass substrates there are other binders which are easily to use in such substrates for shot period and long period also .
if you need further details let me know...
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I want to grow graphene by CVD on different Ni thickness like 50 nm, 100 nm, 200 nm. Is it possible to grow? I want to know about the specific conditions at which it is possible. Please let me know if you have any idea about that.
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Thanks for the helpful suggestion. But there are some limitation regarding minimum thickness of Nickel required to grow Graphene. In a paper, I read that we can not go down below 270 nm thick nickel layer to grow graphene because of vaporization of Ni film.
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During Polysilicon LPCVD deposition, some protrusions or polysilicon horns appeared at the Silicon wafer surface. Does someone have some data on this, that is to say some article on this phenomena the mean to identify the contaminant (by shape correlation or physical/chemical analysis).
Regards
Mohamed
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Hello
i got this issue in the past; We called them polysilicon filaments or "worms". We traced it back to the equipment exhaust pipes which were not 316 stainless steel as specified. The metallic contaminants were able to backstream into the deposition chamber.Once the exhaust pipes were changed, the issue disappeared.
Hope this helps;
Hervé
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Thin film of PANI deposited by CBD on silicon substrate posses no peak from XRD measurement while the bulk sample obtained from the same procedure posses peaks at low 2theta angle (~ 10 - 30 degree). Any theoretical explanation to substantiate these results?
Thank you in anticipation for your helpful contributions.
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Dear Balogun,
 thanks for telling the film thickness.
At the film thickness you have, there are about 1500  to 2000 atomic layers. Altough your PANI molecules exhibit a lot atoms (about 60) you can expect about  30 molecular layers. At such relatively large number of molecular layers I think your film should be able to built up crystallites which are large enough to lead to crystalline type of XRD pattern.
For one to e.g. about  three  molecular layers I would exclude significant crystallite formation due to the lack of sufficient amount of material. 
In your case  the production conditions and/or the following treatment(s) may be responsible for the observed difference in XRD pattern type. 
Is your bulk sample also grown on the same type of substrate and were the surface preparation conditions (cleanliness/cleaning, polishing, etc.) of both substrates the same?
Is the amorphous state of your thin film reproducible?
You see, there are a lot of variables which could affect the type of your film.
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I am depositing indium oxide thin film (30 nano meter) and nano wire (200 nano meter) on p-type Si substrate using E-beam evaporator.I want to known whether oxygen vacancies play any major in indium oxide, and how it can alternate the optical, structural and electrical properties of indium oxide.
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Oxygen vacancies increase the carrier density and by consequence the conductivity of the transparent conductive oxide. One oxygen vacancy creates basically two free carriers and is a strong scattering centre (reduces mobility of the free carriers more strongly than for instance a Sn dopant atom in ITO). Also, oxygen vacancies are not always stable: they can disappear over time. I did a recent study on this in ITO (with low % Sn) and used extra hydrogen in the magnetron sputtering plasma to increase the oxygen vacancy concentration. When working at elevated substrate temp. (about 200°C), the oxygen vacancies remained stable. For RT deposition this is normally not the case.
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Hello all, 
I have a problem depositing a thin SiO2 film by PECVD onto a Au substrate. The  adhesion between SiO2 and Au is poor and I could not deposit Au and then SiO2 using the same equipment under vacuum. I am wondering if there is a way for me to improve the adhesion. Would a Cr layer between Au and SiO2 work (I could deposit Au and Cr with the same equipment)? Thank you very much!
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yes sure, because Au is a noble metal which do not react easily to other layers. So you must deposite some other layer like Cr, Ti as a adhesive layer before deposition of SiO2 which makes a proper bonding to oxigen of sio2.
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hello to everyone. I want to simulate the optical properties of glad deposition (Zig Zag thin film deposition) .
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 I have two articles that may be of help: 
In the first one, the zigzags were small and the film was treated as biaxial with the same coordinates as the ellipsometry system.  In the second one, we treated films with tilted columns.  If the zigzags are large, you have to treat each zig or zag as a tilted column. 
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How can I measure the electrical resistivity of a thin polymeric film?
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Hi Mahdieh,
Besides the two-point measurement technique well explained by Professor Eldenglawey, there is also the four-point measurement technique. You can find more details about both these techniques in the attached file below.
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i have sncl2 and ethanol and i do not have sncl4. is it enough to create a spraying solution for spray pyrolysis method by dissolving sncl2 in ethanol to create a transparent conductive oxide on a glass substrate?
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SnCl2 gets hydrolysed in water.  You will not get a clear solution. Once you add  a few drops fo HCL,  it turns into a clear  solution.  Sn2+ gets converted to Sn 4+. It is as good as starting with SnCl4.  If SnCl2 gets  completed  dissolved in Ethanol, then the solution mostly contains Sn2+ ions and on pyrolysis ,  it gets converted to SnO/SnO2 based on susbtrate temperature.  The resistivity would be high.
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I intend to make a thin film capacitor using solution processing. Alumina is used as dielectric layer and is coated on ITO coated glass via spin coating. ITO works as a bottom electrode for capacitor. The top electrode is made by silver paste. Initially the there is no contact between the two electrode but after sometime the two electrode is shorted and resistance between the two electrode is in Mega ohms. How can I prevent the shorting of two electrodes?
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Hi Bikesh,
Thanks for the additional information. At 100nm defects (particles, voids, bubbles) can have a large effect on your leaking behaviour. Similar tests we did in the past for passive components with PECVD Si3N4 revealed high defect densities at 100 nm.
So it is very important you work in an cleanroom environment, use very clean spinning chemicals (preferably filtered for particles point of use) and clean equipment.
As for the paste, it is silver dissolved in chemicals which could diffuse into the sample. I think that depends a lot on your curing method for the paste. Certain ions (e.g. Ag+ but also Na+ and K+) have high diffusion coefficients in dielectrics (e.g. SiO2) and can lead to a direct shortage path but can also be a source of mobile charge in the dielectric. This has been described in literature extensively and the most common method to detect mobile charge in oxides is TVS (triangular voltage sweep). Where the smaller ions like Na are usually active at room temperature some ions start contributing to leakage current at higher temperatures (K, Ag).
As suggested earlier, to test for this I would just put on a sputtered contact of Al or Cr. 
Did you inspect your alumina for particles, voids, bubbles etc. in dark field microscopy? You can get a fairly good inpression of the defect density by making some pictures and counting the number of defects (irregularities) per area.
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When annealing thin film at constant temperature for different times, the crystalline size (D) decreased and also the resistance (R) decreased. Both parameters lead to increase the sensitivity which is good for my sensor, but it is not right phenomenon to decrease D after annealing! Can anyone help me to explain this? In normal cases D must increased through annealing and R must decreased. If D increased the sensitivity will decrease which is not provide benefit for the sensor!
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Hi Fayroz
  What your are observing in your case is quite interesting. But as per my knowledge with decrease in crystallite size the electrical resistance should increase due to the increase in the grain boundary. This is because the electron will suffer more scattering. 
But as it is opposite in your case again you have to recheck with the crystallite size calculation. I also want to mention that please use the proper K value in the Scherrer equation by checking your film morphology as its value varies from 0.62 to 2.08.
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I used TMM to design a series of Anti-reflection  coatings (ARC) for a mc-Si cell using Matlab. However can this technique accommodate the effects of an absorbing substrate in its formalism? 
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Hi Johann, thanks for the answer. However making the substrate (silicon) absorptive has the effect of creating additional energy within the system at low wavelengths (300nm -400nm), and this effect is only removed if the structure modeled has the same absorption range as the substrate. 
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Hi everyone,
      We have prepared a sample of multilayer thin films of TiO2/SiO2 onto the glass substrate by spin coating.
While doing reflectance measurement (using specular reflectance attachment at 5/15 degree with Shimadzu UV-1800) the reflectance value goes to 115/120/128%.
Can anyone suggest how to shootout this problem or what  is the possible cause of it?
Thanks in advance.
R S Dubey
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Well, you can do that with some special optical equipment, where the main light beam is splitted by a beam-splitter, one of the beam is used as the reference, and the other one as the measurement-beam. 
If you are trying to measure your sample with just bifurcated optical fibers, this is much more complexe. Their are few options. The first one, is to normalise your curve with the theoretical reflectance of your reference. But any defects or scratches on the aluminum, or even the natif oxide growing on it will reduce its reflectance so that your measurement can still be higher than 1 (100%). 
Or, best solution in your case, to do Transmittance measurement, as your substrat is transparent. As their is no absorption in your stack, R=1-T. 
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I need GaN target to coat film, however, it is difficult to sinter GaN powders into bulk film. Can it be directly used as the target for PLD?
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Dear ZhiPeng,
What film are you going to coat? GaN film? If yes, I don't think it will work because the GaN target will decompose into Ga and N atoms upon laser ablation . You may only get Ga metal deposited onto your substrate as the N will be in gas form and brought away by the vacuum system. If you plan to coat GaN film, you may at least use nitrogen radical (from N plasma) or N cracked from the NH3 on a high temperature substrate.
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  1. On the preparation of WS2 by a one step hydrothermal process we are obtaining a yellowish colour, which resemblance that of the tungsten trioxide. What must we do
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If the WS2 has formed it must be black in color as per my observations of synthesis. As you are saying, the product formed resembles that of WO3 which is yellowish in color, I guess WS2 has not formed in your reaction. Check the possible reasons. May be you need to use some reducing agent (fpr eg. NaBH4) in order make the transition metal to react with the S(2-) to produce WS2. 
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Kindly explain  how should I Fabricate cell.
What I do is
1. Taking Mo coated glass slide and protect corners using polyamide tape during spin coating of czts.
2. After spin coating polyamide tape is removed and sample is annealed at 550 I'm h2s. (may be problem starts here. Since the part protected by tape now loses conductivity during h2s annealing)
3. Than I deposit cds, Zno and Al:zno after protecting the back contact again with polyamide tape (temperature sustainability upto 250C).
4. Finally I take IV between Mo and Azo. I am not making grids and to improve voc scribe the cells into smaller area cells.
My jsc and voc is coming good but fill factor is below 30 what should I do?
What is the standard way to protect back contact?
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Reduction of fill factor may generally originate from the series resistance of your solar cell
this could be due to the Mo/CZTS contact , CZTS  , CdS layers resistivity and the different  interfaces quality
try to avoid using a plolymer mask that could be a contamination source , use for example simply a glass slide to cover the Mo electrode.
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What could be the reason for the pin holes on thin film  ? The roughness of the film is around 0.40 nm 
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Hi Johneph,
As Gerhard Martens pointed out, your layer is very thin and you have to account for the growth model and I doubt that you have a continous layer. Normally PVD films are optical closed layers after you deposit ca. 50 nm of material. You can easily check this by sputtering several thicknesses of layers on glass and looking through it to see the pinholes. With a metallic layer like gold this is easy to check. Mind you that Au can grow differently on glass than it will on Si but you will get some idea. As mentioned by others you can also not exclude particles to be the cause of the pinholes. With such thin layers very small particles (and there are many of them in a vacuum system) can destroy a nice conformal coating. That said, I think the argumentation of the layer growing towards a continous layer is your main problem.
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CuInS2 thin film cleaning 
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hi Emre
Did you mean to dissolve CIS2 or just etch surface of CIS2 thin films.
Various etchant are available like NH4S , KCN or hydrazine other than highly acidic solution mentioned in earlier answers.
Be careful while using KCN and Hydrazine , They are highly toxic and cause instant death, Follow appropriate safety methods. 
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Dears, 
I have conducted the X-ray reflectivity experiments in situ and get more than 645 data. I hope to conduct the parratt fitting for these data and get the information about the thickness, roughness, and SLD. But, I cannot found some software which can support the batch fitting. If possible, could you please to  inform me some software and tell me how to use it?
Thanks very much for your help.
Sincerely
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GenX (linked below) is a flexible Python program which you can use for specular XRR fitting by Parratt recursion. It can be run as part of a batch process and parallelized if necessary.
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Dear all,
I am looking for a water soluble material to make a clear thin film (thickness can be as large as 0.5mm), and its refractive index should be near 1.43-1.44.
I tried PVA (RI=1.50), the outcome is not desirable. I am going to try using PEG (RI=1.47) later, but I believe its RI is still too big for my application.
If anyone had a idea for that, please advice! Thanks a lot!
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Thanks Kai and Alan!
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I want to see how the oxygen octahedra rotations are behaving on different samples
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You must check the {0, 1/2, 1} . This one means that the pattern is family of reflections, which is related to the cation displacement but also with octahedral distortions. If your films are a0 a+a0 or a-a+a-(in Glazer Notation) you would expect the (0 1/2 1) or (1 1/2 0) for the permitted reflections and viceversa...
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I'm currently working on chromium-gold thin films for MEMS applications. I'm studying the diffusion of chromium through the gold top film and its oxidation during heating processes and then "natural" ageing of the film (as diffusion and oxidation continue to occur after the chips have been processed and packaged).
We're currently testing different ways to limitate and/or stabilize this diffusion and oxidation phenomenon in order to stop the evolution of the metallisation characteristics.
Any ideas about this ?
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Hi Julie
You can’t prevent this happening, other than having the whole system at absolute zero.  You can slow the process down with an appropriate barrier layer but even this doesn’t substantially reduce the diffusion.  Diffusion is modeled with Fick’s Law.  Take a look at:
August 13th, 2015 The importance of the measurement of diffusion in 2-phase systems
The time taken, t, to diffuse a distance, d, is given by: t = d2/2Ds where Ds is the diffusion coefficient.  Typical solid-solid diffusion constants are of the order of 10E-12 m2/s at room temperature (see some of the plots in the webinar) and thus the time for typical atoms to diffuse a micron is t = (1 X 10E-6)2/(2 X 10E-12] ~ 0.5 seconds.  Raise the temperature and you can guess what happens!  Also, gold is a large atom and will force its way through grain boundaries and defects in the structure (see von Hevesy). The diffusion of gold in molten lead at 250 C is quicker than that of common salt in water. Look for a classic paper by the Chemist of the Mint in 1896 – W C Roberts-Austen, Diffusion of Molten Metals.
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How to avoid the Glow discharge during sputtering . During deposition the Voltage ramps upto 3 times higher than usual sputtering voltage and there  is very less plasma generated and no films were deposited.The problem started after around 4 samples being deposited .
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Some other simple yet possible problem could be loss of magnetization if you are using a magnetron.  Happened in my old lab after somebody forgot to switch on the cooling water and fried the magnets,  i. e.  diode configuration,  no electron confinement,  high voltage,  low deposition rate.
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Thanks for your attention.
I have some question about the expansion mechanism of the hydrogel film, like expansion behaviors of the dry hydrogel in the saturate vapor pressure condition.( Macromolecules, 41(9), 3209–3218. http://doi.org/10.1021/ma7027775)
There was already some discussion about the expansion of hydrogel in water solution:
In the solution condition, some chemical group in the polymers, like carboxylic acid or amine, would be hydrolysed with the water. Then the changed  group could repel each other and the polymers would be forced to expand. 
However, i cannot make sure whether this theory can be applied in the previous paper. In this paper, the expansion mechanism is not detailed.  But it have pointed "pure PNIPAM homopolymer films miss the possibility of internal cross-links to build up a gel". I'm confusing about this point. For the thin film, dose it mean that the pure PNIPAM homopolymer film cannot form the hydrogel structure, or lose the expansion ability? If the discussion about the expansion mechanism, as noted above, is true, i think the cross-links structure would not be necessary for the expansion in the thin film condition.
Anyway, i'm just the beginner in this field. If possible, could you share me some discussion about this topic?
Thanks very much for your time. 
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role of crosslinking is to prevent full dissolution. Also, the higher degree of crosslinking, which limits swelling mechanically, the smaller rate and extent of swelling. If you keep saturated vapor conditions for long enough time hydrophilic polymer will eventually dissolve. If you start with saturated vapor conditions hydrated polymer film will get in equilibrium with a defined vapor pressure.
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Hello
I am making model HDPE and LDPE thin films ( 20nm) on silicon wafers and gold carriers for analysis and further adsorption tests. I am using thin L/HDPE sheets dissolved in Toulene at 72 degrees and then dip coating the carriers.  The goal is to create model layers that mimic the inner surface of HDPE containers. I have analysed the composition and morphology of my samples to that of the HDPe containers. 
Which properties ( roughness, composition, wettability, stability during dynamic stress?) would have to be comparable between the 'real' sample and my model thin films, for me to conclude that my model samples are representative of the 'real life' material.
What is a acceptable deviation (of characteristics) from the real model to make the same conclusion... 
Would it be possible to dissolve the piece cut out of the container in Toulene, make thin films with that and then put through the analysis. ( My gut tells me this may not be that easy)...
Thanks !
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Which properties are relevant totally depends on the things you want your sample to be a model for, so what do you want to research with with your model samples?
For most things I think it is important that your films have a comparable roughness as the inside of the containers you want to model. This can be measured by AFM I think, and that does not require you to dissolve parts of the container, I think you can directly measure on a piece that you have cut from your container (maybe you have to glue it on something else to make it fit properly in the substrate holder of the AFM.
Dissolving and redepositing of pieces of container will probably change the morphology of the material, so that will probably not be suitable for a lot of tests.
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I have synthesized nanoparticles (insoluble in water) out of which I want to make a film on glass. Can anyone suggest an ideal method for the same?
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Dear Hassan,
Thank you very much for your reply. Would you please tell me how much PVA has to be added in how much water to make the perfect solution? Besides, can the stirring be done at room temperature? When shall I add my nanoparticles? Shall I add PVA and the nanoparticles together or I will add the nanoparticles after PVA gets dissolved completely?
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Are there any methods to determine whether by measurement or calculation in order to determine the work function of Indium Tin Oxide (ITO) thin films?
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 XPS is generally used to measure ITO work function.  You can also easily determine it from a graph plot of Ek Vs freq derived from the photoelectric effect equation ( Ek = hf -phi). The y - intercept  is phi, the work function.
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Although I've read a lot about thin-film hydration method, I don't really get the critical points of it. Such as, whether we should add water drop wise or the hole water. I'm working on mPEG-PCL copolymer. Besides, I like to know  I can use centrifuge to omit the drug which are not loaded in micelles or not. 
If someone knows a complete reference about this method, please let me know the citation. 
Thanks
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Adding water dropwise will definitely effect the stability and the size of your micelles. The major points remains the concentration ratios of surfactant, water and your materials in order to form a stable micelles, basically take guard of CMC and HLB of your materials. Slow, dropwise and steady delivering of water willl make the micelles more stable.
You can use centrifuge to omit the unloaded drug but before that just optimize the RPM speed at which your nave micelles must be stable.
For more details go through these links these may give a little more insight.
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I have been exploring possible ways to release thin films off bulk silicon wafers. I have been using a sacrificial layer of Cr/Al but in order take that layer off it takes 1-2 days in salt water. I am looking for something that needs little or no exposure to water during release 
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Look into sacritical aluminium etching ( SALE). Alternatively polyimide or bcb can be used as a sacrificial layer.
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What are the strategies of achieving low resistivity and high transmission at the same time in fluorine-doped tin oxide tin films prepared by spray pyrolysis or chemical bath deposition techniques?
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Fluorine doped Tin Oxide by spray pyrolysis requires optimization of various parameters starting with the processing of the precussor to the deposition conditions. There are different set up for spray pyrolysis that have been reported in literature, some manufactured and others 'home made'. This has lead to variations in optimizing conditions  such as substrate distance, flow rate etc. For you to obtain crystalline FTO, the deposition temperature of the substrate should be around 450 degrees during the deposition process. You can try to optimize other conditions basing on your set up. 
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Besides purity, is there any advantage of sputtering technology over thermal evaporation for making metallised films? Which one is better if less adhesion is required on same substrate ?
Is there any difference in the final appearance of the film made using these two technologies - texture or gloss wise
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The film quality in sputtering is better than thermal evaporation or e-beam evaporation. But in some cases sputtering can not be used because it can damage the substrate or devices.
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The cif file for SnO2:F transparent conductor thin film 
Thanks in advance 
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I have performed anodization on mechanically polished and on chemically polished Ta samples at 15,25,50 V. This resulted in nano porosity on the surface of pore size from 25 -75 nm as voltage increased. Now the Ra value of surface decreased for chemically polished Ta (it increased when mechanically polished sample was anodized). Even though surface roughness decreased, the static friction coefficient of Ta in contact with artificial bone (Epoxy resin reinforced wth glass fiber) increased from 0.37 (etched) to 0.42 (anodized at 15V) and 0.41 at 25 V. Can someone provide an explanation of this?
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Dear Ayesha Khalid, it is a quite interesting effect that you observed. It is not so surprising to me that mechanically and chemically polishing resulted in different roughness after anodizing showing the larger roughness value for the mechanically polished one. Mechanically polishing is achieved by plastic Deformation which will Change the surface Crystal structure more or less intensively. By anodizing you may etch These uneven polishing pits / layers more easily off the less disturbed structure below it which results in a larger roughness than anodizing an only chemically polished surface where you remove rather gentle Atom by Atom directly from the surface without any plastic Deformation.
So now you end up with a lower surface roughness but higher friction. This reminds me about a similar effect when shifting a very flat and low roughness metal part onto another similar one. They Show very high friction and this 'connection' can bear rather high normal loads. The Explanation is, that by the shifting Motion the surface layers of air is removed and there is Little space between the 2 flat and low roughness faces to allow for Oxygen or moisture molecule to go in or stay. A low surface pressure holds them together and, possibly higher van der Waals Forces, due to the smaller distance of the 2 parts.
Since in your case the only similarity is the lower surface roughness and the nanostructuring of the surface, it might be related also to the surface pressure or surface Tension generated by the nanostructuring. Do you really generate pores or are they looking more like pits? However by nanostructuring you also generate more defined contacts that act together between two joined materials / parts than if you have rougher surfaces. 
The question is what are the tribological conditions when joining the two parts (Ta and the epoxy glass fiber: dry? bolt in hole? Fitting Diameters?)?   
Why did static friction of nano textured Tantalum surface treated by anodization at 15,25,50 V increase even though surface roughness decreased? - ResearchGate. Available from: https://www.researchgate.net/post/Why_did_static_friction_of_nano_textured_Tantalum_surface_treated_by_anodization_at_15_25_50_V_increase_even_though_surface_roughness_decreased#576ba8f748954ce9b008eb6e [accessed Jun 23, 2016].
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Actually I have prepared some thin film on glass substrate. to use these as electrode in liquid junction solar cells I am interested to immersed the  substrate in electrolyte.
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Dear Binod
If you are not working at temperatures more than 400 K you can use silver paste but you have to check that silver is not diffusing in your sample if you are using it as electrodes. Silver has high tendency to diffuse thermally as well as on light shining as seen in case of amorphous films of chalcogenides.
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The general formula given in many literature's
H(final)=H(meas.)-N(demag factor)*Ms(Saturation magnetization)
Does any one knows the formula for calculation of N for ultrathin film (total film thickness=1.8nm) with size(4x4 square mm)??
If N=0.5 Ms=1.0Tesla
How do we subtract demag. factors from the real field???
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I am trying to make CZTS thin film using solgel method. Salts that I am using are Copper acetate monohydrate , zinc acetate dihydrate and tin chloride dihydrate with thiourea as a sulphur source. 
As I increase the number coating beyond 5 layers, cracks start to develop in the precursor film.
Thank you
Jitendra Kumar
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Hi jitendra
The cracking in paste occurs due to pressure build up during heating.  you may have to optimize viscosity of paste and heat from top side not from bottom side.
it may help you.
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Normally epoxy based resins are used for glob topping gold or aluminium wire bonds. Does anyone know of other materials which could be used for this purpose?
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Hi Artem,
Thanks for your input. Could hyou eleborate a bit more on the cast variant and how this process is being done?
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Vanadium oxide thin films prepared at different temperature from 473 K - 773 K with the step width of 50 K by using automatic spray pyrolysis technique.
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Dear colleague Rahul S. Ingole ,
Have a nice time and good day.
This can be partially explained using the density of states model in amorphous solids
proposed by Mott and Davis [N.F. Mott, E.A. Davis, Electronic Processes in Non-
Crystalline Materials, Clarendon Press, Oxford, 1979,p. 210, and M. Dongol, M. Abou Zied,
G.A. Gamal, A. EI-Denglawey, Physica B 353 (2004) 169–175].
According to this model, the width of the localized states nearthe mobility edge depends on the degree of disorder and on the defects present in the amorphous structure. In particular, it is known that unsaturated bonds are responsible for the formation of some defects in amorphous solids. Such defects produce localized states in the band structure.
The presence of a high concentration of localized states is responsible for relatively
low values of the optical gap in the case of as-deposited amorphous films. According to the
thermal literature and the bond strength, the process of heat treatment
may increase or decrease the unsaturated defects or localized states;
1-       The unsaturated defects or localized states may gradually annealed out (decreases), producing a large number of structure bonds. The reduction of the number of unsaturated defects reduces the density of localized states and shifts the amorphous to crystalline state
and in the band structure and consequently increases the optical gap.
2-      The process of heat treatment [which represents your case] may affect the bond strength and break the atomic bonds and produces dangling or unsaturated bonds or localized states. The resultant is reducing the ordering of the material and increasing the density of disorder. So the localized states and the amorphous state are increasing and the shift of crystalline to amorphous state is dominant. Such this effect can be easily detected by X-ray diffraction (XRD), Scanning electron microscope(SEM) and   Transmission electron microscope (TEM). You can distinguish between the amorphous, poly crystalline and the crystalline materials through the aforementioned three techniques:1- XRD the produced curve of  amorphous materials has a broad hump and no any sharp diffraction peaks, the presence of sharp diffraction peaks is an indication of crystalline material. 2-  SEM of of amorphous material don't release any features and no particles can be distinguished  otherwise crystalline material. 3- TEM of  amorphous material contains a hallow (white) and no diffraction rings otherwise crystalline material. 4- The presence of spotlight is an indication of single crystals. I wish this issue is useful. Check the attached files.
I wish this issue is useful.
yours
A. El-Denglawey
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working with acrylic resin and system is forced drying
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Then you can go for wft of 100 micron.
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I know that usually ZnS is deposited by RF system, but now only DC and pulse sputtering system in our laboratory. So can we deposit ZnS using DC or pulse sputtering system?
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ZnS is dielectric, but you can sputter it using DC-p power supply. Tunning pulse profiles you have to be able to sputter it. Some related work is available at literature
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I'm preparing polystyrene thin film in ranged from 40 nm to 400 nm. The solutions were prepared from 0.5 wt% to 4 wt% in tolurene solvent. Does anyone know the prebaking recipe on hot plate? Baking temperature and baking duration on hot plate.
Thanks
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Please find attached file. It might be helpful. And also go through below links for more details. 
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Thank you
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Nanoscratch can be used to measure nano-hardness of materials. For more details go through below link. This article might be helpful. 
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What kind of technology is suitable for the surface weight measurement of an opaque thin film ? (the weight is in the range of nanogram)
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ok ! Many thank's
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Hi
I was wondering how carrier scattering varies with the defects in thin film semiconductors. For example if iii-V semiconductor grows on silicon substrate because of the lattice mismatch there will be lot of misfit dislocations and growth twins. Is there any straight forward answer where it can be said that the carrier scattering increases/decreases with line defects or stacking faults. Or if I pose the question like this: how the mobility  is affected by these defects. Will it increase or decrease by these defects? Or is it complicated to say? There exist lot of literature which mostly are misleading or I did not find very good answer in literature which can straight way gun down the question. Some literature says carrier scattering will be more with twin length some says it would decrease with coherent twin boundary length as twin boundaries are low scattering centers. I am not sure how to interpret. In my case I got twin formation between film and the substrate which drastically increases the conductivity. I am not sure whether to interpret that twin boundaries played a dominant role to reduce the carrier scattering and thus enhanced the mobility and conductivity or it has no effect on carrier mobility or scattering.  Your thoughts will be highly appreciable.
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Ankurda,
Usually in nitride semiconductors heterojunctions there are various factors responsible for scattering mechanism,e.g.:acoustic phonon, optical phonon, ionized impurity, interface roughness, surface donor and most importantly threading dislocations. Under different ranges of temperatures one or other factor becomes more dominant than the other. In case of nitrides the dislocations are found to be more benign than other semiconductors. Generally , if the distance between two neighboring dislocations are longer than the scattering length of the electrons, no more further reduction of dislocations are of any help to enhance the mobility of the 2DEG formed at the heterojunction of AlGaN/GaN. Under that situation other factors need to taken care of.
Thanks
Abheek
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Hi Everyone,
I would like to know if there are any other methods to determine charge mobility apart from traditional time of flight methods etc., A method wherein you can measure if there is a change in mobility in the thin film of nm range (~100-500). Further, is it possible to measure carrier mobility in a vertical device? (example in a sandwiched configuration). I have come across literature wherein they have used impedance/admittance to measure the mobility. Does a I-V curve with a Space charge limited Current regime with definite parameters help in extracting any information regarding mobility? How well will the method apply to organic semiconductors?
Can anyone suggest me a starting point.
Regards,
Ram.
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Hi Prof. Abdelhalim,
Thank you very much for the information. I will go through the paper you had sent. Just a question though. So, to have measured a particular type of carrier mobility, it becomes necessary to make either hole only device/electron only device? or is the procedure applicable to any configuration? for example ITO/active layer/Al
Warm wishes,
Ram.
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For forming thin film of metal doped nano TiO2, glass or Silicon surface is preferred and of what size?
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Dear colleague Manasi Karkare,
Have a nice time and good day,
Silicon is better as substrate specially in case of annealing at different temperature.
The size always depends on the sample holder of SEM, so firstly ask for the sample holder. loge time ago i used substrate with dimensions 2cm x 2 cm.
Wishing for you all the best.
yours
A. El-Denglawey 
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I want to know if there is a way to determine the specific types of  dominant scattering mechanism of fluorine-doped tin oxide thin films samples. 
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Thank you very much Dr Denglawey for sending me many articles related to my question. I really find them helpful. Thank you once again. 
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We prepared thin films (30 nm) of Cu3NbSe4 and the measured direct band gap is around 1.5 eV higher than that obtained for bulk samples.
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Dear Prof. P. Grima Gallardo 
Have a good luck
The energy band gap Eg depends on many parameters, the most important one is the crystal structure of the material, if it is crystalline or amorphous, even the crystalline material may have different crystal structures. This depends on the preparation process and the preparative conditions, as well as the growth process and the compactness of its atoms. Consequently, the bulk materials itself may have varying values of energy gap. Moreover, in case of thin films the energy band gap dependence on the film thickness, the used substrate and their preparation. So, You can get such this difference between Eg values of bulk and thin films.
God bless You, and I hope for you a good luck
Yours,
Ahmed Saeed Hassanien
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Hi.
I want to measure the electrical properties of an insulating 10-nm-thin film deposited on a bottom electrode.  How should I deposit the top electrodes? and are the dimensions of top electrodes important?
Thanks.
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thanks dear Ramesh...
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Hello all 
I have taken AFM of my sample, which are thin films ( must be in <50nm thickness). I did the AFM measurements and I wonder the value called Ra( average roughness which is called the mean height) could be considered as height of the thin films grown over my substrate? Is it ok to report the Ra value as thickness of my thin films? 
I would be happy to clarify my question if there exist any doubts. Thank you.
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Short answers: NO and NO.
Longer answers: The value Ra is an average over all topography. It is not a measurement over a step of a film. So, Ra is not a height of a film, and it is wrong to report it as a thickness of a film. The better choice is to measure thickness by measuring across a boundary line that separates uncoated and coated regions.
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The films can be deposited on a substrate that would enable a thickness measurement, e.g. glass, silicon, etc.  I would also appreciate advice on depositing very thin metal films by thermal evaporation.
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 you can use spectroscopic ellipsometry and by choosing the convenient model and get the best fit you will find the layer`s thikness.
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we already had NiO nanoparticles. Could you suggest us how to use NiO nanoparticles by spin-coating and form a thin film? For example, what kind of solvent we should use to make suspension solution? and the concentration of the solution in order not to have aggregation in resultant film?
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Yes dear
I think it is better to specify the solvent based of the successful trail of Vikas Patil et al. on the following link.
They used m-cresol to dissolve nanocrystalline NiO powder under continuous stirring, but in your case, the stirring power and the require time will depend on the agglomeration degree of your own powder however you can find these parameters experimentally. The concentration of the NiO in solution will affect only the film thickness. This also can be investigated experimentally.    
Best regard
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I need these values, in order to study the work function of pseudo alloy contact materials, namely AgZnO(92/8), AgCdO (88/12) and AgSnO2 (88/12).
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Prof. Akbi,
At least some of your compounds are semiconductors. In semiconductors the WF is highly dependent of the free carrier type and concentration, which are dictated by the type, energy level and concentration of dopants and defects. Therefore, typically there is no simple answer to your question. If we were talking about standard, production-grade semiconductors such as Si and GaAs then given the dopant it would take one simple equation to determine the WF. However, for the materials you discuss, I suspect that the situation is not that simple; in these cases the carrier concentration is often defect-dominated, and such effects are usually inconsistent between different labs and processes (although, perhaps for some specific cases it is known that common defects induce degenerate doping pushing the Fermi level into a known band position).
Usually the electron affinity isn't as strongly dependent of the doping and defects of the semiconductors, which could make it more convenient for comparing different semiconductors. I believe that this value should be easier to find in the literature.
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Hello,please any one knows the values of both richardson constant of CZTS thin film and the electronic affinity of zinc sulfide(ZnS)?.
thank's 
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İf you construct p-CZTS/metal Schottky junction, you can measure Richardson constant from temperature dependent Current - voltage measurement.
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I am investigating the process of encapsulating a very thin (20 micron) polyvinyl alcohol film inside a Hydroxyethyl methacrylate based, cross-linked, hydrogel.  The PVA film needs to be able to dissolve into a clear, low water content, liqui-gel, with some shape memory.  My issue is that the PVA film dissolves nicely but continues to absorb saline until it ruptures the encapsulating hydrogel.  I have been adjusting the molecular weight and the degree of hydrolysis and also the concentration of PVA along with crosslinking with Freeze/Thaw cycles, Glutaraldehyde or Sodium Tetraborate to try and control the end point swelling.   
Additionally when I reduce the PVA concentration to around 1% and cast in 20 micron aluminum mold, the dehydrated film is often too thin to remove from the mold ( but 10% de-molds and handles well, though at that concentration it appears to cause over swelling ). I have also tried glycerin as a thickening/plasticizer and a mold release agent like PS80 but no luck at the 1% concentration level. 
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Ali Nematollahzadeh
Clever! I will give it a try.
Thanks
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 I am currently running my photocurrent analysis with MoO3 thin film in Na2SO4 electrolyte (pH=1.50). When I apply the potential from 0 V to 2.0V, the I-V curve is abnormal. The onset potential was located at potential of 1.6V. 
What I expected is the onset potential should located between the range of 0V to 1V. When I applied 0V to 1V of potential, I-V curve gave my a horizontal straight line. Anyone can help me on what is really going on? Appreciated much for any help.
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Hi, Did you check your electrode connection very well?
Then , i am working on SrTiO3 photoanode, I use applied potential in the range of ( -0.9 V to +0.9 V) to measure  its photoelectrochemical properties .
all the best
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I have some multilayer MoS2. 
But the surface of MoS2 have some oxidation after some time.
Now i can't measure the PL like the original MoS2.
How can i remove the oxidation or recover the surface from MoS2?
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Remove the oxidation from mos2 surface possible to use with common acids (such as hydrochloric acid, nitric acid and sulphuric acid).
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I have taken the PL spectrum for my transition Metal (TM) doped ZnO thin films. I have obtained a Peak at 490 nm. In some reprints it was mentioned as green emission and in some reprints it was measured as blue emission. Which one is right? I have used an excitation wavelength 325 nm.
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 See attached - 490 is in between.