Thin Films and Nanotechnology

Thin Films and Nanotechnology

  • Ali. Gholami Zali asked a question:
    New
    How can I produce a UV curable antiscratch solution?

    I need to produce a UV curable transparent anti-scratch solution for being cured on the surface of a polymeric film.  

  • Vishwanath Hiremath added an answer:
    59
    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.
    Vishwanath Hiremath

    @suchitrs sen ... The two peaks were observed in the plot of absorbance vs. Wavelength.

    However, when i plot for ahv vs hv the curve seeems smooth.

  • Bruno Azambre added an answer:
    3
    Someone can suggest me possible applications using core@shell Fe3O4@mesoporousSiO2?

    I have synthesised Fe3O4 nanoparticles (ca. 80-200 nm) and covered by mesoporous silica (ca. 20-40 nm, see the attached TEM image) and they can be heated by microwave. What I am looking for is doing heterogeneous catalysis. I wanted to do liquid adsorption but I can't due to the some technical issues.

    Bruno Azambre

    Hi, I would propose two things:

    - to use it for (photo)Fenton-like catalyst in presence of H2O2 for the oxidation of pollutants (by generating OH radicals using the Fe(III)/Fe(II) couple), but the interest in using a mesoporous silica shell has to be clarified (shape selectivity, improved adsorption ?)

    - to fill the silica pores with organic grafts (designed for specific adsorption purposes) or embedded metallic agents (for catalysis or specific adsorption) and then to take advantage of the presence of the magnetic Fe3O4 core for easy separation of the catalyst from wastewaters (no filtration needed).

    Hope it helps.

  • Li Yang added an answer:
    3
    How to calculate the theorectic capacity of NMC 622 and NMC 811?

    How to calculate the theoretic capacity of NMC 622 and NMC 811:

    If Co is +3 and Mn is +4;

    is the Ni in the fully lithiated states +2.66 of NMC622 and +2.875 of NMC811. So the calculated capacity (not consider Co +3 activity) is 221 and 248 mAh/g, respectively?

    Thanks in advance.

    Li Yang

    Thanks for this...

  • Massimo Tallarida added an answer:
    16
    What features/factors would you look for in an Atomic Layer Deposition (ALD) Reactor?
    As we have been spreading the word about ALD and its usefulness we have found many people who haven't heard of the technique. We are working on putting together an economical ALD reactor that is more versatile than some of the more expensive systems. We believe that by lowering the cost of quality equipment more researchers will have access to ALD. In pursuit of that we are asking for your input.

    What features would you like to have in an ALD system?
    Massimo Tallarida

    Well, I write not to answer to the questions, but rather to invite you to the workshop "Synchrotron Radiation to study Atomic Layer Deposition". We will also talk about the way to construct ALD reactors!

    Bests,

    Massimo

    + 1 more attachment

  • Ilija Nasov added an answer:
    5
    Does anyone know a thin layer coating (probably multi layers) that gives >97% transmission when coated on glass?

    Does anyone know a thin layer coating (probably multi layers) that gives >97% transmission when coated on glass?

    Ilija Nasov

    My answer was related to PVD selective coatings.

    The best transparency we received with PVD SiO2 coating .

  • Yuri Mirgorod added an answer:
    1
    How to make nanoribbon layer on ag substrate for SERS?

    To make excellent SERS substrate.

    Yuri Mirgorod

    Dear Megha: It all depends on your task. If you want to make a uniform substrate for the fixation of the molecules, it is a difficult task. Silver nanoparticles may be the substrate. They are easily synthesized from many ion reducing agents. These reducing agents may be, stabilizers. They give SERS.

  • Waqee ur Rehman added an answer:
    98
    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.
    Waqee ur Rehman

    Oladunni Jimoh,

    there are too many structures of TiO2, but sending you some of them

    + 6 more attachments

  • Ao Zeng asked a question:
    New
    How to measure the exact volume of a Natrix hydrogel thin film?

    How to measure the exact volume of a Natrix hydrogel thin film?

  • Tanuj Trivedi added an answer:
    1
    Could you please suggest recipes for selective etching of Ti on Ti/AlN or Ti/GaN interfaces?

    Good day. 

    We are working with Ti/GaN and Ti/AlN. We deposit 100-300 nm of Ti on GaN or on AlN. 

    After some treatment we need etch Ti without influence on AlN and GaN.

    Could you please suggest steps, dry (DRIE) or wet (acids etc.) etching?

    Thank you very much!

    --
    Best regards,
    Dr. Petro Deminskyi
    Academic Secretary
    SRI of Microdevices NAS of Ukraine

    Bilkent University, UNAM
    BIYIKLI Research Group
    Department of Material Science & Nanotechnology

    Tanuj Trivedi

    Both Ti and GaN are typically etched using Chlorine chemistries in RIE/ICP dry etching. If you want to use dry etching, you may have to establish a recipe specific to your thicknesses based on some available data. Although I suspect that even a fine tuned recipe may lead to some surface roughness on your GaN films.

    Here is a good paper on Ti ICP etching: http://engineering.ucsb.edu/~memsucsb/Research/publications/parker_electrochem05.pdf

    Alternatively, you could use a mix of wet etching to remove Ti/TiO2. BYU clean room website has some information on wet etching for metals (look up titanium on the page): http://www.cleanroom.byu.edu/wet_etch.phtml

    You can compare the etch rates of some of the Ti etchants with GaN. Here is one paper on GaN wet etching: http://www.csmantech.org/Digests/2006/2006%20Digests/6C.pdf

    I don't think a highly selective etch exists between Ti and GaN. If it is possible for you to deposit a very thin etch stop layer (some other dielectric such as SiO2 or Al2O3) between Ti and GaN, that may be a more favorable solution.

  • Jose Hodak added an answer:
    1
    Is there a method to link a PEG film to Silicium or Solicium oxyd bed?

    I want to create a film of ~1µm of PEG (Mw 900 000 or lower) linked to a Silicium wafer, SiO2 or SiOH bed. Is there a method to do it, Thanks

    Jose Hodak

    In  my opinion, for a film of 1 micrometer thick it would not make any difference whether it is bound chemically or just deposited on the substrate. The reason for this is that there is  sufficient molecular interaction at the boundary to hold the film.  You can try to deposit this film from a concentrated solution of PEG in water by dip coating or spin coating. If you find that one coat from a very concentrated (viscous) solution of PEG does not give you uniform films, try multiple coats  by spin coating from a more dilute solution. Thickness can be measured by elypsometry or by interference. If would If you need to link it chemically, you may need to form epoxide or ester groups between a previously derivatized silicon (or silicon oxide) substrate and the PEG. 

  • Morteza Amjadi added an answer:
    3
    How to make uniform and homogeneous film of dispersed cnt?

    how to make uniform and homogeneous film of dispersed cnt?

    Morteza Amjadi

    You also can try air-spray coating as a very simple way to coat the CNT solution over your substrate. Check out my recent paper:

    https://www.researchgate.net/publication/280245490_Ultra-Stretchable_and_Skin-Mountable_Strain_Sensors_using_Carbon_Nanotubes-Ecoflex_Nanocomposites

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: Super-stretchable, skin-mountable, and ultra-soft strain sensors are presented by using carbon nanotube percolation network-silicone rubber nanocomposite thin films. The applicability of the strain sensors as epidermal electronic systems, in which mechanical compliance like human skin and high stretchability (ε>100%) are required, has been explored. The sensitivity of strain sensors could be tuned by the number density of the carbon nanotube percolation network. Strain sensors show an excellent hysteresis performance at different strain levels and rates with high linearity and small drift. We found that carbon nanotubes-silicone rubber based strain sensors possess super-stretchability and high reliability for strains as large as 500%. Nanocomposite thin films exhibit high robustness and excellent resistance-strain dependency for over ~ 1380% of mechanical strain. Finally, we performed the skin motion detection by mounting the strain sensors in different parts of the body. The maximum induced strains by the bending of the finger, wrist, and elbow were measured to be ~ 42%, 45% and 63%, respectively.
      Full-text · Article · Jul 2015 · Nanotechnology
  • D. K. Dhruv added an answer:
    6
    How to take TEM for thin film samples on glass or Si substrates? Is any other method apart from ion milling?

    Since I am working on solid state solar cells, hole transporting layer (~50 nm) has been optimized as an initiative to fabricate a device. Now I would like to take TEM for that layer. Hence i am asking this question to the experts. 

    D. K. Dhruv

    Hello Mr., the following is the address where you will find the TEM instrument for the analysis.

    They will analyze your sample once it is taken on copper grid as mentioned by Dr. A. Eldenglawey in his answer.

    Contact me again for analysis help.

    Sardar Patel Centre for Science and Technology
    Vallabh Vidyanagar – 388120,
    Dist: ANAND,
    GUJARAT, INDIA
    Phone: +91-2692-234966
    FAX: +91-2692-238355
    E-mail: sicart_cvm@hotmail.com

    http://www.sicart.res.in/tem.aspx

  • Teresa Diaz Calvo added an answer:
    6
    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.
    Teresa Diaz Calvo

    Hi Yali,

    You could try to stain your coating with a serum albumin antibody conjugated with a fluorescent tag and then, examine it by fluorescent microscopy or with a fluorescence plate reader...hope this helps!

  • Janusz Rebis added an answer:
    10
    HI EVERY ONE , PLEASE HOW CAN I GET ON MODULUS OF ELASTICITY FOR NANOCOMPOSITE MATERIALS (Aluminium as a matrix and carbon nano tube as a reinforced )

    E for aluminium is 70 Gps and for carbon nanotube is 1000 Gpa 

    Janusz Rebis

    Mohammed naeem Mohammed: sorry for missunderstandig.

  • Yusran Yusran added an answer:
    3
    Dear All, Why do my obtained CV plots looks flip-over of common CV plots for metal oxide supercapacitor?

    Well, I prepared Co3O4/C nanocomposite electrode for supercapacitor material. Confusingly, the obtained CV plot indicates the flip-over figures compared of common CV based metal oxide electrode. Mean at the higher voltage (0.5 V) the the CV plot go down deeply (negative current) and low voltage (0.1) appear  on positive current which presented flip-over cor common pseudocapacitance.

    Yusran Yusran

    Dear Prof. Chen,

    Please find the attachment of CV plot.

  • Remya Aravind added an answer:
    3
    How can we calculate the tolerance factor of La doped BFO where the dopant concentration increases from 0.1 to 0.15 ?

    Please explain the role of coordination number of A and B (in ABO3 perovskite structure)in finding out the tolerance factor.

    Remya Aravind

    thanks alot  Samaa El-Dek and Jian Wang.. 

  • Bibhuti B Sahu added an answer:
    10
    How can I calculate the Absorption coefficient from Absorbance?

    I prepare thin film of ZnO by pld and measured its Absorbance Uv-Vis ,then i need to Calculate Absorption coefficient  from Uv.Vis. Data.

    Bibhuti B Sahu

    abs. coefficient = 2.303 * Absorbance/ (thickness of the ZnO film)

    Here abs. coefficient represents the Napierian absorption coef!cient
    and the coeficient 2.303 arises from the conversion factor ln(10).

    You can refer the paper:

    Plasma Sources Sci. Technol. 25 (2016) 015017

    Good luck!

  • Timofey Golubev added an answer:
    4
    What is the best method to make a 1-2mm thick PDMS stamp out of Sylgard 184 Silicone Elastomer Kit?

    I have seen procedures suggesting repeat spin-coating and curing. Others suggest simply pouring into a mold to desired thickness and curing. 

    I would like to use the stamp for transfer of nanostructures between substrates as described in the link.

    Thanks

    Timofey Golubev

    Thanks for your suggestions. I've been able to make PDMS by pouring method. After degassing the viscous mixture, I found that very slowly pouring onto cleaned glass microscope slides introduces minimal bubbles which go away after leaving it in ambient for ~30min. I was able to remove the cured film without too much difficulty as long as it was at least ~0.5mm thick. Of course this method does not yield a perfectly uniform thickness, but that's not necessary for my application.

  • Mohammad Siddiqui added an answer:
    7
    What are the techniques to detect micro cracks in Si wafers?

    What are the techniques to detect micro cracks in Si wafers. Preferably for a bunch of wafers together. I know EL/PL is one technique but it is for individual wafer not a bunch of wafers together. 

    Mohammad Siddiqui

    thanks.  

  • Carlos Araújo Queiroz added an answer:
    3
    How can I dissolve PVDF/CNF completely? What type of solvent is required to completely dissolve CNF/PVDF? For Electrospinning process?

    As a part of developing nanofiber composite sensor. I Need to disperse CNF completely in PVDF (i tried up using DMF..it results poor dispersion) so suggest some good solvent to disperse CNF completely in PVDF for electrospinning process

    Carlos Araújo Queiroz

    Also about solvents for poly(vinylidene fluoride), i.e. PVDF: https://www.researchgate.net/post/How_can_I_dissolve_PVDF_What_kind_of_solvent_completely_dissolve_PVDF_and_is_not_toxic_I_know_nMP_and_MEK_but_I_dont_want_to_use_anything_toxic

  • Dilek Şura Özden added an answer:
    31
    What could be an alternative for hydrofluoric acid in etching titanium metal?
    I will be working with the Titanium etching and is going to use Hydrofluoric acid to etch, but now I wanted to replace it with some other etchant because of its hazardous nature. Can anyone suggest an Etchant which does not involve HF acid?
  • Aperam GERALDO Alves added an answer:
    7
    What is the IR Vibration at 2000cm-1 on LaFeO3-xNx perovskite thin film?

    I've synthesized LaFeO3-xNx thin film by magnetron sputtering. The amount of nitrogen is very low (few %at). On FTIR measurements I observe a vibration mode position at around 2000cm-1, that I cannot attribute (vibration mode of the perovskite are situated from 100 to 600cm-1).

    This should be due to N=N link, but it has to be link with something to get a IR vibration.

    Do you have an idea to see such a vibration by other method (I'm currently doing RAMAN spectra)?

    Does anyone already observe similar vibration mode position in nitrogen containing sample?

    Thanks

    Aperam GERALDO Alves
    I am not a practicing XPS spectroscopist,
  • Julio Cárabe added an answer:
    5
    Why conductivity of P-doped Si film decreases after certain level of doping?

    Effect of dopant on p-doped amorphous Si films?

    Julio Cárabe

    When you add boron or phosphorus to your Si lattice, an important fraction thereof is incorporated as dopant atoms (via tetrahedral coordination, i.e., by establishing four hybrid sp3 orbitals and therefore imitating and replacing silicon) but also a fraction incorporates to the lattice without doing so (i.e. keeping the original 2p or 2p3 orbital(s)). These latter atoms do not behave as dopants (do not create any free electron or hole), but rather act as recombination centres, since their presence in the lattice distorts its overal order. The more you dope the silicon, the more boron or phosphorus defects you insert in the lattice. When the concentration of such non-tetrahedrally bonded atoms becomes large enough, the lost in carrier lifetime and mobility overcomes the effect ot the free carriers created by the addition of tetrahedrally-bonded dopant atoms.

    The effect is more pronounced when doping with boron because this atom is appreciably smaller than that of silicon, whereas phosphorus atoms are nearly equal to silicon atoms in size. Phosphorus is more sucessful in imitating silicon than boron is.

  • Shigeo Kubota added an answer:
    2
    Does IAD coating degrade over time compared to IBS coating?

    Hi,

    Is it true that at first IAD and IBS coated optical elements may behave similarly, but over time the IAD coating may peel off or degrade, especially when exposed to humidity or high-power laser radiation?

    Thanks,

    Assaf

    Shigeo Kubota

    Assaf,   I will refer two sites.

    http://www.reoinc.com/technical-resources/cat/78/technical_tutorials/article/Coating_Process_Tutorial

    Coating process difference:   “IAD is a variant of the electron-beam evaporation process which adds a high energy ion beam that is directed at the part to be coated….  In IBS, a high energy ion beam is directed at a target (metals or oxides). The ions transfer their momentum to the target material, causing atoms or molecules to sputter off.  These high energy atoms then deposit onto the parts to be coated.”

    This difference makes difference in the packing density in coating layers which is responsible to imperviousness to water vapor.

    “The high energy of the ion beam sputtering process results in extremely uniform, high density, completely amorphous films with excellent adhesion to the substrate."

    This advantage is also claimed by another coating company.”

    http://advancedthinfilms.com/Capabilities/IBS-Thin-film-Coatings

    Unlike conventional evaporative coatings that have porous microstructures, IBS thin films have densely packed structures that make them impervious to water vapor. Consequently, our IBS coatings are insensitive to changes in environmental conditions such as heat, humidity and pressure.     Shigeo

  • Shehan Perera added an answer:
    4
    How does the enhanced near-field due to nanoparticles increase the absorption in the semiconductor?

    Nano particles are incorporated into various layers of thin film solar cells.  near field enhancement is one way of increasing the photon absorption in the active layer. Can anybody explain to me or recommend to me  a good reference which explain the mechanism of increasing absorption due to near field enhancement? 

    Shehan Perera

    Thanks prof. Abdelhalim Zekry

  • Vladimir Dusevich added an answer:
    5
    Which Pt sputtered coating thickness is the best for SEM-EDX spectroscopy?

    I am doing SEM-EDX spectroscopy but I do not know which thickness of Pt sputtered coating that can give better results, is 20-50 okay?

    Vladimir Dusevich

    If you can, use carbon coating. If not, use as thin coating as possible. I would start with something as low as 3-5 nm; usually good for polished specimens, for fractures may be not enough. If you see charging with thin coating you can always to add a bit, but you cannot remove too thick coat. Check if Pt peaks overlap with some expected elements.

    I think 15 nm is not necessarily the best thickness. 

  • Christian Röling added an answer:
    3
    What is the best method to hydroxylise polysilicon surface with -OH groups?
    I have gone through few methods to hydroxylise the polysilicon surface as the following:
    - Fenton reaction
    - boiling in HNO3 1hr
    - 1:3 (H2SO4:H202) 90c
    Are these methods good for hydroxylating polysi surface? Or is there any other good method for this process?
    Christian Röling

    We work with H2O2/NH3/Milli Q (1:1:5) 70°C 30 min.

    Best regards

    Christian

  • Christian Röling added an answer:
    6
    What are the differences between Silicon and Glass substrates when one wants to get a monolayer of nanoparticles deposited by spin-coating method?

    I am trying to get monolayers of Pt and Pd-Cu nanoparticles deposited on Si by spin-coating method. However, our analysis shows that Pt nanoparticles pile up and Pd-Cu do not adhere to the substrate. We performed several tests and got this. Now, I was wondering about changing the substrate, maybe glass. Can one explain me the differences of using SI and Glass substrates? Or suggest another cheap and affordable substrate to use?

    Thanks!

    Christian Röling

    Or what you can even try is to activate the surface by rinsing the substrate in H2O2/NH3/Milli Q (1:1:5) 70 °C for 30 min. We use it if we want to absorb vesicles on Si or glass.

    Best regards

    Christian

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