Thin Films and Nanotechnology

Thin Films and Nanotechnology

  • Atilla Atli added an answer:
    In nano size, can h, k and l (Miller indices) value together or does one of them have a value and the others are equal to zero?

    I know that in nano size the periodicity of lattice is only in one direction that is why   in nano size can h,k and l  one of them has a value and others equal to zero for example h have the value k and l equal to zero

    k have the value l and h equal to zero

    l have the value k and l h equal to zero

    But most papers showed that nano size but in XRD present h,k and l have the value

    Atilla Atli · École Catholique d'Arts et Métiers

    Thanks a lot Giovanni for your answer. 

  • Mohand Arezki OUADFEL added an answer:
    Can Hall effect equipment be used to determine the type and concentation of charges in a thin films?
    Hall effect applies for relatively thick samples (micro or milli-meter range). What alternative technique would be useful for electrical characterization of a thin film
    Mohand Arezki OUADFEL · Centre de Recherche en Technologie des Semi-conducteurs pour l’Energétique (CRTSE)

    Saurav Kumar is right!!! NB: Hall Effect equipment is to use regularly and very carefully, because of the sensible mechanical parts.

  • Issa M El-Nahhal added an answer:
    Why is p-type ZnO not stable?
    It has been reported that ZnO when doped with various dopants (N,P) become p-type but none is long-lasting. This maybe due to, I believe, diffusion of atmospheric oxygen and interstitial Zn, but I'm not sure. Does anybody have any idea?
    Issa M El-Nahhal · Al-Azhar University - Gaza

    Dear Yuriy

    Is there any dopants that can do the job? I wounder of trying one of transition elements as dopant. What do you think? 

  • Claudia Bojorge added an answer:
    How to estimate the thickness and interface roughness of thin films using X-ray reflectivity spectrum?
    I have deposited CuS thin film on glass substrate and recorded the XRR spectrum. I herewith attached the image of the spectrum. Could anyone suggest me how to calculate the film thickness and interface roughness using the recorded XRR spectrum?
    Claudia Bojorge · Institute of Scientific and Technological Research for the Defense

    Hello Razia: I´ll contact you by email. I just now read your message.

  • Hu Zhu 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.
    Hu Zhu · Université de Montréal

    The problem is the head group. Because of it, MPTMS is far more reluctant to react with glass than APTES does. So under the same conditions, your glass surface is not well dressed with MPTMS, accounting for the failure on AuNPs. To address this problem, you could add some amine into MPTMS/ethanol, which favors the silanezation reaction. 

  • Ravi Kumar Chanana added an answer:
    How can I find the bandgap of SiOxNy accurately, without Internal Photoemission?
    It is a possible alternative high-K dielectric for CMOS technology
    Ravi Kumar Chanana · Galgotias College of Engineering and Technology (GCET)

    Please see my latest featured article for the answer.

  • Xinfu Gu added an answer:
    How to calculate lattice mismatch for epitaxial film?
    I know the lattice mismatch degree is determined by a formula (lattice parameter of material A-lattice parameter of material B)/ lattice parameter of B in most cases. However, recently I found out this formula is not used in the determination of lattice mismatch of epitaxial film on a substrate. I want to ask for a epitaxial film how to obtain its lattice mismatch on a substrate. Thank you.
    Xinfu Gu · Tsinghua University

    The lattice mismatch actually relate to the orientation relationship, or else you need to "guess" which directions is possible to mach together. The latter usually the case when you try to predict the orientation relationship. Anyway, there are two ways, the first one is directly calculate the misfit value, the second one is applying graphic plot to show the match/mismatch.

    (1)For two crystals (1 and 2) at a given orientation relationship, the misfit between two vectors from crystal 1 and 2 can be defined as deta x = x1 - x2. In simple but not strict manner, x1 and x2 connect the nearest atoms from crystal 1 and 2 respectively. For defining the more useful quantity, i.e. misfit strain, which is defined as |deta x|/|x1| with crystal 1 as reference cystal, x1 and x2 should be close to the origin so that they do not cross a dislocation.

    (2)The graphic method is plot the atoms from the two crystals in a plane and denote the atoms with misfit smaller than certain value. This can be done by the software PTCLab, see

  • A. N. Dobrovolsky added an answer:
    Is there any free software that can calculate optical constants from thin films reflect and/or transmetance spectra data?
    Is there any free software that can calculate optical constants from thin films reflect and/or transmetance spectra data in txt or excel files? My films are semi transparent with a unknown thickness but between 50nm and 2minron deposited on glass slides or metaliques substrates
    A. N. Dobrovolsky · Institute of Physics of the National Academy of Science of Ukraine

    Dear Jarmo Maula,

    Thanks a lot for your contribution. :)

  • Thu Vũ 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.
    Thu Vũ · Vietnam Academy of Science and Technology

    hi, any one has the link to download jcpds software?

  • Sanjay Kumar added an answer:
    how to find r.i (n) of thin film from A, R%,T% data?
    I have absorbance, reflectance% and transmittance% data. How to calculate refractive index from this.
    I tried with R = [(n - 1)^2 + K^2 ] / [(n + 1)^2 + K^2] where K is extinction coefficient.
    Calculation was done by numerical method. It shows large deviation from reported value.
    Kindly suggest how to proceed.
    Sanjay Kumar · Central University of Jharkhand


    n1=refractive index of sample

    n2=refractive index of substrate


    you can use this formula

  • Anybody knows a good definition of "phase"?
    Everybody understands things like solid, liquid or gaseous state of substance. We call them solid, liquid or gaseous phases, respectively. This is intuitive but hardly rigorous. Chemists, I'm told, consider a cup of sweetened tea to be a single phase, even when the concentration of sugar at the bottom is maximal and nearly zero at the free surface (no mixing was applied to dissolve the sugar). Is this indeed correct? My own interest, in magnetism, is still another: can I consider two neighboring magnetic domains (or ferroelastic as well) as belonging to two different phases? Or is it the same phase only differently oriented?
    Vishnampet S Vaidhyanathan · University at Buffalo, The State University of New York

    i like David Grier's  description .   what he states is relevant to  phase transitions, whether they are first order or second order etc.,. Simply stated,  when there is a mathematical discontinuity  exists, as a result existence of discontinuites in physical properties, such as density or dielectric coefficient, phases coexist.

  • Andrea Bearzotti added an answer:
    How to determine a thickness of a spin coated polymer film?
    If one cannot afford techniques like AFM and other Profilometric investigations, how will one find out the thickness of a polymer thin film? Can we guess the thickness by knowing the molecular weight, viscocity of the solution and the rpm of spin coating?
    Andrea Bearzotti · National Research Council

    Sri Venkatesh asked for a measurement method EXCLUDING the AFM and profilometer. A possible formula for determining the thickness of a polymer deposited by spin coating (in first approximation ) can be the following:
    where h=film thickness m=fluid viscosity z=angular velocity and t=total spinning time.
    See A. G. Emslie, F. T. Bonner, and L. G. Peck, “Flow of a Viscous Liquid on a Rotating Disk”, J. Appl. Phys. 29, 858-862 (1958).

  • Aucun Jwane added an answer:
    How to improve conductivity of TiO2 sputtered thin film?
    Could you tell me several methods to use?
    Aucun Jwane · University of Strasbourg

    thank you

  • Oren Erich Meiron added an answer:
    Are there any methods to synthesize MoS2 sheet other than mechanical exfoliation?
    I want to synthesize MoS2 sheets or flakes using an easier method, mainly any chemical route other than conventional mechanical exfoliation.
    Oren Erich Meiron · Ben-Gurion University of the Negev

    You have many different methods for producing MoS2 besides mechanical exfoliation (although it is one of the simplest methods). You can find some of the methods in this review:

    *Recent Development of Molybdenum Sulfides as Advanced Electrocatalysts for Hydrogen Evolution Reaction

    Good luck

  • Patitapabana Parida added an answer:
    What is the difference between crystallite size, grain size, and particle size?
    How can we measure these sizes?
    Patitapabana Parida · National Institute of Technology Rourkela

    particle Size: It a measurement of a shape. We can measure the particle size in many different way: 1)Volume based particle size, 2)Weight based particle size, 3)Area based particle size, 4) Hydrodynamic or aerodynamic particle size. There is an International Standard on presenting various characteristic particle sizes.This set of various average sizes includes median size, geometric mean size, average size.
    Grain Size: grain size is the diameter of individual grains in the crystal of a material.

    Best Regards

  • Z. Ben Hamed added an answer:
    How can I grow thin film of porous TiO2 nanotubes over ZnO nanotubes using chemical methods (especially, sol-gel and hydrothermal methods)?

    I want to prepare thin film of porous TiO2 nanotubes over ZnO nanotubes, using ZnO nanotubes itself as template.

    Z. Ben Hamed · University of Tunis El Manar

    i suggest chemical attack for  zno  BULK   and spin-coating  for TIO2  SOLUTION 

  • K.D.M. Rao added an answer:
    How to select a material for memory device?
    Selection parameters of materials for application in memory devices.
    K.D.M. Rao · Jawaharlal Nehru Centre for Advanced Scientific Research

    Resistive switching refers to the physical phenomena where a dielectric suddenly changes its (two terminal) resistance under the action of a strong electric field or current. These are next generation RRAM (Resistive random access memory).

    following are the properties of RRAM, which are better than the existing memory technology. 
     High speed ,Simple structure, Excellent scalability, low power consumption, Simple fabrication, High storage density

    One terabyte of data on a postage stamp size device


  • Toru Hara added an answer:
    What are the potential non-conventional application of ferroelectric thin films?

    I would like to know if there is any other possible applications of ferroelectric thin films (in particular perovskite-like oxides) besides the obvious ones in microelectronics?

    Toru Hara · Nazarbayev University

    How about this?

  • Anders Kvennefors added an answer:
    What is the stopper for CSAR 62 E-Beam resist?
    We forgot to buy the stopper 600-60, but I need to work with it now. May be it is a well known chemical combination.
    Anders Kvennefors · Lund University

    I am a CSAR 62 user, I can confirm that IPA is indeed the stopper.

  • Ivan Culaba added an answer:
    Is it better to grow a thin film of alloy (containing three elements) on any substrate by electron beam evaporation technique?
    Electron beam evaporation.
    Ivan Culaba · Ateneo de Manila University

    Electron beam evaporation is a form of thermal evaporation. So the evaporation temperature of the alloy must be within or below the temperature generated by the electron beam. Otherwise you might have to choose sputtering. With regards to the composition and stoichiometry of the thin film, this can be best answered by actually making the thin film and performing an analysis ( like EDX ). Note that the substrate temperature also has an effect on the film composition. 

    I hope this comment helps.

  • Luisa Ottaviano added an answer:
    Any suggestions on how to improve adhesion of the negative tone resist HSQ to GaAs substrate?
    Adhesion of HSQ to GaAs
    Luisa Ottaviano · Technical University of Denmark

    Hi Diego, I have the same adhesion issue and I have tried to solve it with Surpass3000 without success. Could you please share your process details? Do you spin coat the AlGaAs surface with Surpass or you immerse the sample in a beaker containg the adhesion promoter?

  • Demis John added an answer:
    How do you get an uniform, 50nm film thickness of SU-8 direct on the glass substrate?
    For nanofabrication I need to have a less than 50nm film thickness of SU-8 on the glass substrate. I've tried with spin-coating but it seems that this method doesn't work. Can anyone help me please? Thanks.
    Demis John · Praevium Research, Inc.

    If you don't specifically need SU-8, try Microposit LOL1000 (intended for 50-100nm thick spin coating).

    The datasheet shows that at 5krpm it spins at about 50nm.

  • Ilker Yildiz added an answer:
    Can anyone suggest the most accurate method for calculating the band gap values of powders and thin films materials?
    I am in doubt about which method i may use to calculate band gap of thin films, if the Kubelka-Munk method using diffuse reflectance spectra or the Tauc method using absorption spectra.
    Ilker Yildiz · Middle East Technical University

    Dear John , have you ever done such a measurements  With UPS ?  if so  what do you think about multi layers and thin films and  their measurements ?  Also cleaning the surface can mislead  the their measurement results ? what do you think ? 

  • Khalil Eslami added an answer:
    What are the effects of the surface roughness on Thin film properties?
    I prepared thin films of Pani-DBSA/Natural rubber and characterized their surface morphology by Atomic Force Microscopy. The average roughness is around 60 nm
    Khalil Eslami · Kharazmi University

    It influences on efficiency and contact resistance, so that it modifies the performance of optoelectronic devices.

  • Manohar Sehgal added an answer:
    What is the range of values for Urbach Energy for SnS thin film?
    Could you give some details?
    Manohar Sehgal · DAV College Jalandhar

    The Urbach Enery values decrease after annealing. This decrease is slightly more as the annealing temperature increases which indicates an improvement in the quality of ZnS film on annealing. Its EU value BEFORE annealing is 1.38[eV] or 138 meV and AFTER annealing is1.10eV or 110meV.

    [A][Pls. find attached a five page paper for your kind perusal and authentication [ Look in TABLE- I on the top of PAGE -41 ]
    {B} Pls. find details in your another similar question.

  • Manohar Sehgal added an answer:
    What is the range of values for Urbach Energy for SnS thin film?
    I would appreciate a detailed calculation process.
    Manohar Sehgal · DAV College Jalandhar

    [Pls. find attached a five page paper for your kind perusal and authentication [ Look in TABLE- I on the top of PAGE -41 ]

  • SMJ Mortazavi added an answer:
    How can gamma radiation interact with nanoparticles and make a noticeable difference?

    When metal chalcogen is exposed to gamma radiation, what are parameters that related to nano size?

    SMJ Mortazavi · Shiraz University of Medical Sciences

    Dear David

    Over the past years, we have conducted some experiments on the radiation attenuation properties of nano-sized and micro-sized materials. As you believe that the dose enhancement of nanoparticles is due to 1) increased photoelectric absorption and 2) the emission of auger electrons, can you explain how nano-sized materials have more photoelectric interactions per unit mass for photons with a specific energy?

    We previously showed that nano-structured WO3/PVC samples present a significant greater potential in absorbing low energy X-ray photons compared to that of the samples produced with microstructured WO3/PVC. We also reported that the smaller size of the nano-structured WO3 particles can guarantee a better radiation shielding property. However, we did not study the mechanisms of this phenomena. The abstract of our paper that is published in the Medical Physics International Journal is enclosed.

  • Prateek Kothari added an answer:
    What kind of gases can be used in a RIE to etch Indium doped tin oxide (ITO)?

    I wish to pattern ITO coated glass substrate for QDLED application using a RIE. 

  • Sai Jiao asked a question:
    Can anyone help me find magnetron reactive sputtering information on group III-Nitrides?

    Is there anyone who have experiences using DC Magnetron Reactive Sputtering Systems from the Germany based Company Singulus? What about their AlN ability specifically? and Could you give me some typical material properties if you are one of the users of Singulus Systems? Thanks.

  • Varun Sharma added an answer:
    What is the difference between Atomic Layer Deposition (ALD) and Chemical Vapor Deposition (CVD)?
    Seeking to understand the difference.
    Varun Sharma · Technische Universität Dresden

    Now a days ALD (fast ALD from veeco, and spatial ALD) can achieve high growth rates and better in quality as compared to conventional ALD ALD the chemistry is totally different from the CVD method. However, ALD is subset of CVD. In ALD low temp growths can be achieved in combination with FLASH, PLASMA, LT-remote plasma techniques.

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