Thin Films and Nanotechnology

Thin Films and Nanotechnology

  • Kranthi Kumar added an answer:
    How do I obtain a good suspension of flake graphene for coating on a sensor surface?
    I want to homogeneously coating graphene on a sensor surface.
    Kranthi Kumar · Indian Institute of Science

    Prof. coleman science paper has details about suspension of layered materials

    which uses different solutions and surfactant to do so. 

    check it out.

  • Hyohan Kim added an answer:
    Is there any characterization technique(except XPS) that can provide me with the oxidation state of the metal in the film?

    I need to characterize the oxidation state of the metal in film(to be precise I wish to know whether in the film metal or metal oxide or metal sulfide or combination is present). These films are made of nanoparticles. I need to characterize atleast 10-50nm of the film without destroying the film(if possible)

    Hyohan Kim · Inha University

    FTIR is useful to your analyzing. In lower frequency, metal oxide bonding state will be observed from these spectra. 

  • Hamidreza Hajfarajollah added an answer:
    I want to coat 96 well plates with plasma polymer film. Can anyone tell me if there is a quick way to determine the coverage of the film in the wells?
    (except XPS)? e.g. something that can make the plasma polymer show a certain colour.
    Hamidreza Hajfarajollah · Chemistry & Chemical Engineering Research Center of Iran

    You can not trust on just one test. It would be better to examine FTIR, AFM, XPS and water contact angle simultaneously.

  • Sadhasivam Subramani added an answer:
    Having pure (C-H only) organic material, can Fdd2 space group give ferroelectric behaviour?
    I have basic doubt on this.
    Sadhasivam Subramani · Sri Sivasubramaniya Nadar College of Engineering

    thank you for some suggest...

  • Ravi Ananth added an answer:
    What is the reason of peak shifting in XRD towards higher angle side after the sample has been irradiated?
    Could anyone explain the reason of peak shifting in XRD? Thank you.
    Ravi Ananth · Onsight Technology USA

    Minghui! Sounds like interesting work! Post some of your diffractograms when convenient.

    We must assume any effects due to sample displacement 

    are eliminated. For the generalized question that Arvind posed, the schematics below may be of some help. It is a collage from several sources over the years:-)

  • Sibasish Dutta added an answer:
    What are the chemical methods available for the deposition of silver film of nanometer thickness on glass prism to observe surface plasmon resonance?

    To  deposit silver or gold film of nanometer thickness, we need an expensive Vacuum coating machine. Since such expensive machines cannot be afforded everywhere, how can one deposit silver or gold film of nanometer thickness on a glass prism or glass slides? I mean to say that is there any chemical route available?

    Sibasish Dutta · Tezpur University

    Thank you for your suggestion

  • Albert Juma added an answer:
    How do I find the chemical composition of a thin film from an AFM image?

    I have AFM image of WO3 thin film deposited by r.f. magnetron sputtering. I have the data of arc length of cantiliver and force between atoms on the cantiliver tip and surface atoms.

    Albert Juma · Tallinn University of Technology

    For compositional analysis, there are more direct methods to use like RBS, XPS, XRF, EDS, PIXE, ERDA, SIMS. If such techniques are unavailable, then you need good experience with your AFM to obtain quantifiable data, which will definitely be only surface composition.

  • Ron Reiserer added an answer:
    How can I obtain a thin homogeneous layer of PDMS mixed with a solvent?
    I would like to add a homogeneous layer of pdms mixed with a THF solvent with thickness of a few micrometer or less on to a waveguide structure.

    My current attempts with dip-coating have given me a thickness that increases along the surface to the end-point of the dip-coating. I am doing this by hand since I do not have any special dip-coating device available.

    I have also tried to spin-coating but this have given my bubbles on the surface, which I do not want. The bubbles is probably due to the THF in the pdms as I go to high speeds.

    Any suggestion how I can obtain a thin and smooth homogenous surface of pdms mixed with THF?
    Ron Reiserer · Vanderbilt University

    Can you use cyclohexane instead of THF? You can degas the elastomer base under vacuum then add solvent and mix using a centrifugal mixer then add the curing agent and mix again in the centrifugal mixer. It may be helpful if you can do a dehydration bake of the substrate before deposition.

  • Guang-Wei Wang added an answer:
    Can anyone suggest the most accurate method to calculate "electronic band gap" of thin films?

    I am calculating the optical band gap from UV-Vis absorption data of my thin films. But I want to calculate "electronic band gap" of my thin films

    Guang-Wei Wang · Fudan University

    If you can get the C-V measurement data of a PN junction,you will obtain the dopant concentration of the lower doped region(Nd) and built-in voltage(phi0) of the PN junction.If you have hnown the dopant concentration of the heavier doped region(Na) of the PN junction when you make it,then you can easily get the intrinsic carrier concentration value of the materials you used to make the diode.From the data of  intrinsic carrier concentration,you may calculate the value of electronic energy band gap.I hope it will be helpful to you.

  • Metwally Madkour added an answer:
    How can I calculate the band gap from UV-Vis absorption spectra of thin films consisting of TiO2 and other metal complexes?
    I have prepared thin films of TiO2 and other Metal complex with TiO2 on a glass substrate. I just need to calculate band gaps of materials on the glass substrate.
    Metwally Madkour · Kuwait University

    There is a templete you can apply on it but is complicated so far. i tried it and the results were positive

  • Deepak Sharma added an answer:
    Are there any inter layer materials for tungsten nano film deposition using sputtering?

    Are there interlayer materials like TaN for copper nano film deposition, so that copper doesn't diffuse into a silicon wafer, are there any such materials for tungsten deposition?

    Deepak Sharma · Indian Institute of Science

      So, Does that means diffusivity of W in SiO2 is very less,and if i pass electric current through W films on SiO2, Resistance offered by W will not be high?

  • Vedran Budinski added an answer:
    Does anyone know how to etch the Titanium dioxide (TiO2) from surface of a glass?

    I`ve already deposited TiO2 on my glass substrate and I want to make a pattern on glass/TiO2. If you have any idea please let me know also about the recipe and mixing ratio of acids.

    TiO2 thickness: 800 nm

    Glass thickness: 500 um

    Many thanks~

    Vedran Budinski · University of Maribor

    @ Andrea Foli

    What is the typical etching time of TiO2 in hot sulphuric acid You also heat the acid near boiling point (approx. 337°C)?. I have to deposit about 3 um of TiO2 as a sacrificing layer on a optical fiber.

  • Carlos Araújo Queiroz added an answer:
    How can i clean Nanosticks of TiO2 from Teflon beaker ?
    I want to synthesis TiO2 Nanostructure Using Hydrothermal Methods, unfortunately the Teflon beaker has Nanosticks; not washed it properly after someone else used the beaker to synthesis TiO2 previously. Thus, Could you tell me please, the mechanism/the way to clean the Teflon beaker. Thank you in Advance!
    Carlos Araújo Queiroz · New University of Lisbon

    I agree with Andrea Folli, also suggesting cleaning with hot sulphuric acid followed by neutralization with diluted aqueous alkaline solution and final rinsing with deionized or distilled water.

  • Pathik Kumbhakar added an answer:
    How can I calculate energy density (u) from the gradient of UDEDM plot, in XRD analysis using Williamson-Hall method?
    Any ideas on how to convert the gradient into kJ/m3?
    Pathik Kumbhakar · National Institute of Technology, Durgapur

    You may get details here

    Indian J Phys (March 2014) 88(3):251–257
    DOI 10.1007/s12648-013-0417-y

  • Rainer Wüstneck added an answer:
    What is ostwald ripening and how does it relate to surface area of materials, How the process can be controlled
    Can anyone advise on ostwald ripening?
    Rainer Wüstneck · Max Planck Institute of Colloids and Interfaces

    Ostwald ripening is like real life. Siemens becomes bigger and bigger, and small companies disappear. Area: The area of the lung is high because there are a lot of small departments. So when the number of particles or droplet decrease the surface area of the main surface area decrease as well. Influence: You may change the surface properties of the particles or droplets. If there are ionic groups at the interface you may play around with concentration and kind of counteractions. You can increase the surface charge to create a proper electro-statical repulsion by adsorption of ionic surfactants. If the interface is hydrophobic you may influence the hydration forces by adsorption of nonionic surfactants. You can adsorb polymers to create a surface mechanical barrier..

  • A. R. Lasisi asked a question:
    How does one determine the structure of a thin film deposited on another thin film using XRD?

    How does one determine the structure of a thin film deposited on another thin film using XRD?

  • Ehsan Soheyli added an answer:
    What is the difference between crystallite size, grain size, and particle size?
    How can we measure these sizes?
    Ehsan Soheyli · Arak University

    Thank you Dear Pawel

    That was a wrong in my writing... :-)

  • Kranthi Kumar added an answer:
    Is there any way to know if we have a p-type or n-type XnO:Sb nanowires without measuring the Hall effect?
    Kranthi Kumar · Indian Institute of Science

    I totally agree with Arnab hot probe is the best one

    just put a multimeter on the film which is spin coated by your wires  and just heat one end and check the voltage

  • Gerhard Leichtfried added an answer:
    What is the sintering time and temperature of Ni Ti target for sputtering?
    Most of the people work in the field of research in the field of NiTi, share sputtering condition but not give the NiTi Target sintering process.
    Gerhard Leichtfried · Plansee

    Hi Veeresh?
    What is the composition of the target, you would like to produce? What equipment do you have (hot isostatic press, vacuum sintering furnace,..)?

    If you have a HIP, I would propose the following process:
    - Pressing the powder
    - Putting the green part in a Ti can
    - Evacuating the can
    - Sealing the can
    - Compacting the material in a HIP at a temperature depending on the composition (but clearly below the eutectic temperature) under a pressure of > 1000 bar.

    Best regards

  • Angela S Pereira added an answer:
    Reliable protocol for mercapo-silanes on glass?
    I am trying to bind gold nanoparticles to functionalized glass surfaces (optical fibers in particular) and the simple protocol I use works GREAT with 3-aminopropyltrimethoxysilanes, but fails regularly with 3-mercaptapropyltrimethoxysilane! The protocol is as follows:

    Clean fibers in pirhana (30min)
    Rinse with anhydrous ethanol.
    Immerse in anhydrous ethanol, add MPTMS/APTMS at 1% by volume for 1 hour.
    Remove and rinse with ethanol.
    Store fibers in ethanol until use.

    The weird part is I've had at least one trial where the MPTMS worked great. (I evaluate the efficacy by monitoring nanoparticles depositing on my fibers in realtime with UV-Vis). I am amenable to any suggestions and really have no idea why this protocol worked really great once, but mostly fails. I have tweaked most parameters such as immersion times, heating vs. non-heating etc.

    It's really confusing to me why this doesn't work since the only difference in these molecules is the headgroup.
    Angela S Pereira · University of Aveiro

    What type of amine would you suggest Hu?

  • Abdul Rauf Bhatti added an answer:
    How can I extract the values of data plotted in a graph which is available in pdf form?
    Abdul Rauf Bhatti · Universiti Teknologi Malaysia

    Please click the link below to download it.

  • H. Frielinghaus added an answer:
    What is the basic principle of SAXS?
    What happens inside the sample, please give me theoretical background with explanation.
    H. Frielinghaus · Forschungszentrum Jülich

    There are some of my talks in my download section - for SANS, i.e. neutrons. But SAXS is mentioned as well. Another good book is published by Roe: "Methods of x-ray and neutron scattering in polymer science".

  • Aisha Tanvir added an answer:
    Is anyone familiar with the handling of electrospun nanofibres sheet/mesh?

    I get a nice uniform sheet of electrospun nanofibres, however after some time when it dries out the sheet starts cracking into pieces, making it very hard to transfer the sheet onto something else.

    I am collecting the nanofibres on aluminium foil, I would like the nanofibres to stay as a film, any suggestions on how to do that. Existing literature doesn't mention anything about this.....

    Aisha Tanvir · Qatar University

    Dear Parmiss,

    Wouldnt making a paste result in loss of nanofiber structure?

  • Boon-Hong Wee added an answer:
    What kind of probe station is suitable for measuring photoconductivity?
    A light sensitive thin film was coated onto a PET substrate. In order to measure its photoconductivity, what kind of probe station (type of probe tip) is suitable? I have two different probe tips (gold and tungsten), which one is suitable?
    Boon-Hong Wee · University of Incheon

    Thanks alot for the information.

  • Vladimir Burtman added an answer:
    Is there any difference between electrical band gap and optical band gap?
    Dear All
    Is there any difference between electrical band gap and optical band gap?
    If so can we relate them?
    Please answer
    Vladimir Burtman · University of Utah

    Hi Alexandre, this  is my reference:

    emperature Dependent Barrier Crossover Regime in Tunneling Single Molecular Devices Based on the Matrix of Isolated Molecules by Andrei V. Pakoulev, Vladimir Burtman, JPC 2009.

    Please note that experimental details are extremely important in proper responce to your question. 

    I also recommend you to review the whole  2013 (Summer) issue of Natural Materials on Nano-electronics. Good luck! V

  • A. Tiburcio-Silver added an answer:
    Which method would be applicable to calculate the electric field intensity at grain boundary of polycrystalline metal oxide film?
    I would calculate electric field intensity at grain boundary of polycrystalline metal oxide films.
    A. Tiburcio-Silver · Instituto Tecnológico de Toluca

    You can get the average height of the grain boundary potential (a most important parameter) by measuring the Hall electrical mobility versus temperature. It's almost impossible to get the width of the depletion region in a polycrystalline material, as we have a wide range of grain sizes (and from here, we can have grains completely depleted and others only partially emptied).

  • W. A. W. Razali added an answer:
    Why I cannot get Alumina particle in nanosize scale using ball milling method?
    Several milling sessions using 5mm, 1mm and 0.2 mm grinding ball were carried out to produce alumina nanoparticle while water was used as a surfactant. Most of the milled powder cannot achieved nanosize scale and tend to agglomerate/stick on grinding jar. Charge ratio has been adjusted from 5 to 100 but still unsuccessful. Can anyone suggest a solution?
    W. A. W. Razali · Macquarie University

    Dear all,

    I have figure out that the ball milling belt for the bowl was broken.

    so annoying..

  • Oseoghaghare Okobiah added an answer:
    How to search data of xrd from JCPDS number?
    I want to know how to search data if I know JCPDS number.
    Example I knew my JCDPS number it's JCDPS #800075.
    I want to use data with my XRD research graph.
    Oseoghaghare Okobiah · University of North Texas

    Hi Please can someone send me the  JCPDS card for  #39-1346. Thanks

  • Manohar Sehgal added an answer:
    Can anyone suggest what can be obtained by urbach energy?
    I am referring to calculated urbach energy at band gap edge for undoped and copper zno nanoparticles.
    Manohar Sehgal · DAV College Jalandhar

    [A] If it does not come up to expectatiions, treat is as an unfruitful academic discussion without any prejudices . Some times , I have a lurking fear, yet the teacher in me compels me to put forth an idea. Once I had to listen sermons from a celebrated RG colleage to study more even in the eight decade of my life.
    [B]Apply Tauc and Meneth :
    α -------A/ hv[hv-Eg]^n
    where A is a constant while n can have values ½,2,3/2 and 3 for allowed
    direct, allowed indirect and forbidden direct and indirect transitions respectively.
    Plot a graph between[ ln(α )] and [hv] . May extrapolate if needed; slope gives Eo so that value of α becomes α0 and the following relation holds good:
    α --------- α0 [exp(E/E0)]
    where E is the photon enegy.
    After having calculated Eo, we apply the relation
    α=αo exp [(hv - Eo)/∆E]
    α=αo exp [(hv - Eo)/EU]
    where ∆E or EU is called the Urbach Energy or Urbach tail or Urbach width.
    which can be calculated as all other parameters in the above relation are known.

  • F. Caballero-Briones added an answer:
    What is the range of values for Urbach Energy for SnS thin film?
    I would appreciate a detailed calculation process.
    F. Caballero-Briones · National Polytechnic Institute-CICATA Altamira

    The procedure mentioned by Manohar to calculate Urbach tail parameter in ZnS films is essentially correct, although the original question was about SnS. The values of Urbach tail parameter are dependent on the origin of the tail, for example, dislocation density, presence of active electrical/optical impurities including self doping for example by S vacancies, lack or increase of crystallinity and so on. You can do the calculations for Urbach parameter for your SnS samples by the suggested procedure and try to relate the values you get with the structure, the electrical behavior, composition and so on. Find a detailed treatment on the origin of Urbach tails in semiconductors in the following papers. We also have a couple of papers where the aforementioned correlations of Urbach parameter with impurities, microstructure, carrier density were made.

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