Thin Films and Nanotechnology

Thin Films and Nanotechnology

  • Ł. Skowroński added an answer:
    Details on Tauc Lorentz Parameters in Spectroscopic ellipsometry Fitting?

    Hi every body!

    To those who use the Software S.E.A.from the Sopra Firm , to perform fits of their experimental data collected from a spectroscopic ellipsometer. Can you help me about Tauc Lorentz fit parameters? Give their definitions and In what range they must vary in order to have a good fit, of Tg(Psi) and Cos(Delta) for example? Thak you.

    Ł. Skowroński · University of Technology and Life Sciences in Bydgoszcz

    Hi Mohand,

    I’m a user of WASE ellipsometer, but maybe information below can solve your problem:

    In my publication:
    https://www.researchgate.net/publication/267868470_Characterisation_of_coloured_TiOxTiglass_systems
    I have been used T-L model to parameterize optical properties of TiOx film deposited on Ti thick layer.
    In Fig.7 I present the example of the fit. In pages 4 and 5 I showed expressions and found parameters of Tauc-Lorentz oscillator with uncertainty.

  • Tarik Ömer Oğurtani asked a question:
    How do you obtain the apparent diffusivity coefficient by knowing the thickness versus annealing time data?

    Since TiN  system seems after the diffusion of copper very thin layer of Cux Ti1-x N nonstoichometric compound having almost negligible amount of concentration gradient. But  there is still a non-vanishing copper flux goes through this surface layer and then penetrated to TiN matrix!  Problem here how can one analyze this problem which shows  almost zero concentration gradient but finite flux in term of diffusion coefficient defined by Fick's  first law?

  • C S Naveen added an answer:
    Is carbon dioxide a educing gas? Does it increase the conductivity of n type ZnO?

    I am working on the topic entitled, ”Synthesis and Characterization of ZnO nanoparticles for gas sensor application”. I would like to know whether carbon dioxide is reducing gas or not and does it increase the conductivity of n-type ZnO after purging the same in to the test chamber

    C S Naveen · Kuvempu University

    @Alexander Tolstov and @Georgii Sokolsky: Thank you very much

  • A. B. Shcherbakov added an answer:
    Does anyone know the recipe for etching the silver in AAO template?

    i want to etch (remove) silver (Ag) from AAO template.Based on finding in internet, to etch silver, we need HNO3 and H2O. i need suggestion from others about the ratio@percentage on using these chemical. 

    A. B. Shcherbakov · National Academy of Sciences of Ukraine

    I think it's reasonable to try weak hydrogen peroxide. It's "soft etcher" for metallic silver and indifferent to hydrated aluminia (unlike acids/alkalis).

  • Shrikant Bhagwat added an answer:
    Can Hexamethylenetetramine (Hexamine) be used to synthesize Amine functionalized Iron Oxide magnetic nanoparticles?

    Commonly used reagents for amine group functionalization on the surface of magnetic particles are ethylenediamine, 1,6-hexanediamine and (3-Aminopropyl)triethoxylsilane.(APTES). Despite the presence of four amine groups(tetramine) and the low cost of hexamine, it is not used extensively for the above mentioned purpose.

    Shrikant Bhagwat · Tomas Bata University in Zlín

    Hexamine is a caged molecule with tertiary nitrogen atoms and when it decomposed in to ammonia and formaldehyde. so amine functionalization is difficult

  • Bulkesh Siwach added an answer:
    What is the best binder for carbon black and multiwall carbon nanotubes?

    I am making the carbon black and carbon black/mwcnt counter electrode for dye sensitized solar cell. Is it cmc or something better?

    Bulkesh Siwach · Guru Jambheshwar University of Science & Technology

    Thanks..Rajesh

  • F. Jimenez-Villacorta added an answer:
    What are the reasons for inconsistency in resistivity and Hall Effect measurements of ZnO thin films by Van der Pauw Method?
    I am trying for electrical resistivity and Hall Effect measurements of Physical Vapour deposited ZnO thin films (of about 300 nm) by Van der Pauw Method with 1500 Gauss of magnetic field, Keithley 6220 current source and Keithley 2000 DMM. I have made the electrical contact with silver paste. I was not giving any heat treatments for silver paste contact. But I am not getting consistent and repetitive readings for voltages for the sample. Even If I am trying for direct resistance measurement with Keithley 2000 DMM, I am getting continuously, exponentially increasing resistance as time progresses. I am not getting the reason for these fluctuations.

    Whether the problem is with the silver paste ohmic contact? Please anybody can help me the procedure of making ohmic contact with silver paste? What are the optimum drying condition/ temperature for silver paste contact? How to check the certainty of ohmic contact? Is it by linear IV curve?

    How much gauss of Magnetic field is suitable? Whether the problem with the thin film sample? Why the resistance exponentially increases continuously?
    F. Jimenez-Villacorta · Spanish National Research Council

    Have you observed exponential variations of resistivity with time (covering periods of minutes)? I am not an expert, but they might be related to a curious effect called (I don't know why) "persistent photoresistance". Here some examples:

    - Solid State Communications 149 (2009) 1347

    - Solid State Communications 151 (2011) 1700

    - J Vac Sci Technol A 31 (2013) 01A146

    - Appl. Phys. Lett. 99 (2011) 112503

    I hope it helps...

  • Hooman Rahmani added an answer:
    How to use sources which have low vapor pressure in ALD?

    In ALD, we will encounter some sources which have very low vapor pressure or the source just cannot have a big dose when you even use a long dose time. Usually, we use source heater, but find even with high temperature, we cannot have a big dose. 

    In these cases, what can we do to make source an enough source dose for the reaction?

  • Elif Oz Orhan added an answer:
    How way I can increase the carrier mobility in a semiconductor thin film without change any other parameters?

    I am working on the field of the solar cells. It is important to improve the carrier mobility for this case.

    Elif Oz Orhan · University of Maryland, Baltimore County

    The conductivity of a semiconducting material, in addition to being dependent on electron and/or hole concentrations, is also a function of the charge carriers’ mobilities, that is, the ease with which electrons and holes are transported through the crystal. Furthermore, magnitudes of electron and hole mobilities are influenced by the presence of those same crystalline defects that are responsible for the scattering of electrons in metals—thermal vibrations (i.e., temperature) and impurity atoms. Influence of dopant, at dopant concentrations less than about 10 20 m-3, both carrier mobilities are at their maximum levels and independent of the doping concentration. In addition, both mobilities decrease with increasing impurity content. For dopant concentrations of 10 24 m-3 and below, both electron and hole mobilities decrease in magnitude with rising temperature; again, this effect is due to enhanced thermal scattering of the carriers. For both electrons and holes, and dopant levels less than 1020 -3, the dependence of mobility on temperature is independent of acceptor/donor concentration.

  • 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

    Dear all, you might want to read a manuscript which tackles the problem from the neutron view - but it is the same for x-rays. In my datasets you will find the article "Nanostructures Investigated by Small Angle Neutron Scattering Lecture Notes for the JCNS Neutron Lab Course in Jülich/Garching 2013".

  • Michael Pan'kin added an answer:
    Where can I look for the total scattering cross section from N2 at 0-30 eV ?

    How to look for the total scattering cross section from N2 at 0-30 eV?

  • Ayuba Fasasi added an answer:
    Does anyone know of a physical method to obtain nanoparticles?
    There are several chemical methods to synthesize nanoparticles of gold, silver, and iron oxide, as co-precipitation or thermal decomposition. But physical methods either are not widely known or publicized. There is the laser ablation in a liquid medium, which can obtain any type of nanoparticles, but lasers for this technique are expensive. Does anyone know a way to make it cheaper or other physical process to obtain nanoparticles?
    Ayuba Fasasi · Phillips 66

    Have you tried Physical vapor deposition(PVD)?

  • Sashika Kusal Hemachandra added an answer:
    How can we perform synthesis of graphene oxide by plasma chemical vapor deposition?

    please i need this

    Sashika Kusal Hemachandra · Wayamba University of Sri lanka

    Hello,

    I think this article might help you to deposit Graphene in plasma-assisted chemical vapor deposition technique.

  • Johan Frans Prins added an answer:
    What is the main idea behind thin film superconductivity?

    If there are no long range order in thin films, how one can claim the Cooper pair mechanism exists in amorphous materials?

    Johan Frans Prins · Sage Wise 66 (Pty) Ltd

    I wanted to comment but after reading Behnam Farid's convoluted irrelevant mathematical arguments, I despair. As long as there is a high enough density of localised states, a percolation threshold can be reached beyond which supercopnduction will occur no matter what the long-range order is.

  • Arpita Mitra added an answer:
    What are the factors for Aluminum thin film depostion when Rf sputtering is used?

    The following are the main factors I found that affect the deposition rate of aluminum when RF sputtering technique is used for film deposition.

    1. base pressure

    2. sputter pressure

    3. power

    4. temperature

    I want to know how the deposition rate changes when each one of them is changed. It would be great if there was a research paper where they have done a DOE on this data for multiple factors analysis.

    Thank you

  • F. Caballero-Briones added an answer:
    What is the equivalent weight of Indium Tin Oxide (ITO) ?

    Equivalent weight of ITO and valency of ITO ?

    F. Caballero-Briones · National Polytechnic Institute-CICATA Altamira

    Do you mean the formula weight? 

    There are a couple of reported formulae corresponding to the crystallographic charts 32-458 and  39-1058 of the PDF Database, In2SnO5 and In2Sn2O7-x respectively.

    Thus you can calculate the formula weight that best fits your samples.

  • Firman Mangasa added an answer:
    Can anyone explain why IGZO films obtained by sputtering only in argon ambient has a very high resistance?

    I am working on thin film transistors with Indium gallium zinc oxide (IGZO) as the channel material. I am using RF sputtering for IGZO deposition. I am doing it in only Argon ambient. Since the conduction mechanism in IGZO is due to oxygen vacancies, only argon ambient should give me films with high carrier concentration but I am obtaining films with very high resistance. Can anyone please suggest why this might be happening?

    Firman Mangasa · National Chiao Tung University

    If the EDAX result shows high O concentration, therefore I believe, the problem is the film lack of oxygen vacancy not due to the excess of it.

    Can you confirm it by XPS O1s spectra? Conductive film should show very-very low intensity of lattice Oxygen (@ lowest eV) as compare to the non-lattice one (@ medium eV) and absorbed Oxygen (@ highest eV). Please see the attachment for your references, the figure is Al-doped ZnO film that I am working on.

    If 4-probes arent possible, please use multimeter. I know it ll be not accurate at all, however at least you know the tendency of your film resistivity.

    Usually using 100 Watt, 0.005mBar, Ar (only) flow should be okay.
    Probably, we miss some other parameter.
    Can you tell us the base pressure?

  • Huie Zhu added an answer:
    Why does my Polythiophene film show low current with applied voltage, only several picoA? How can I increase current flow in such films?

    Why does my Polythiophene film show low current with applied voltage, only several picoA? How can I increase current flow in such films? 

    Huie Zhu · Tohoku University

    Thank all comments. Prof. Dr. A. Kumar,I use deposited gold layers as electrical contacts. I am thinking about the doping in the next step as Bernhard  and Dirk suggested. 

  • Carlos Fuhrhop added an answer:
    How can I obtain aligned nanofibers by ES?

    I tried to electrospin a magnetized polymer solution in the presence of a magnetic field but did not get any alignment at all. The setup I use is quite simple, 2 magnets are placed paralled to each other at varying distance and the magnetized polymer solution is electrospun and the fibers are collected between the magnets.

    The idea behind this is that since the polymer solution is magnetized(fe304 dispersed in the polymer sol.) the nanofibers will automatically align themselves due to the external magnetic field.

    I would appreciate some input from people who have experience in this, or maybe another method(not too complicated) to obtain aligned nanofibers?

    Carlos Fuhrhop · Leuphana University Lüneburg

    Dear Aisha,

    this paper can be help you and also can be download from Researchgate:

    Christian Grasl et al., Electrodynamic control of the nanofiber alignment during electrospinning. APPLIED PHYSICS LETTERS 102, 053111 (2013).

    Best regards,

    Carlos Fuhrhop

  • Nadiir Bheekhun added an answer:
    Does a nanostructured material at micron-size produce a bimodal coating structure when thermally sprayed?

    Greetings,

    I've come across queries regarding nanostructured thermally sprayed coatings and I'd like to clear my doubts to some extent.

    It is clear enough that to obtain a nanostructured coating, one should use nanosized particles but agglomerated into micron-size before spraying or opts for suspension spraying.

    Well, suppose we have a nanostructured material which consists of nano-sized particles and pores and this material is physically in powder form at micron-level within the range for thermal spray.

    If one decides to spray the latter as it is but wants to keep the nano-structural characteristics by preventing all the particles to be fully molten, will the resulting coating be a bimodal one?

    The confusing part here is the fact that the spraying feedstock powder is in micron-size without agglomeration but consists of nano-structural properties and we want to keep these in the coating.

    I'd really appreciate for any clarifications.

    Cheers,

    Nadiir

    Nadiir Bheekhun · Putra University, Malaysia

    Alright Doc. I'll do that. Thank you!

  • What is the effect of infrared radiation on Coumarin 30 doped in PMMA?
    Is it okay to use Coumarin 30 doped PMMA for fluorescence measurement over the spectrum from 500nm to 900nm? If not, then what are the limitations?
    Shaban Ahmed Ali Abdel-Raheem · Agricultural Research Center, Egypt

    http://www.google.com.eg/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CDIQFjAE&url=http%3A%2F%2Fdigital.csic.es%2Fbitstream%2F10261%2F21562%2F1%2FGetPDFServlet.pdf&ei=AEqHVLz-CNLlaJnbgrgN&usg=AFQjCNF9VFRHkDvuOVCHEjolufJfR6x5_w&bvm=bv.81449611,d.bGQ

  • Carlos Araújo Queiroz added an answer:
    How to control thikness variation of a thin polymer plate?

    Some times at the exit of the extrusion machine, a plate of polymer (2mm in thickness ) will suffer reduction in its thickness. This situation rise to a weak mechanical resistant in this area. So I look for an optical idea to control this plate. with my Kind regards

    Carlos Araújo Queiroz · New University of Lisbon

    You may possibly find interesting the following reference:

    S. Nuyan, J. Graeffe and H. Moisio, "Recent advances in online caliper measurement", Pulp & Paper Canada, 108(11) November 2007, pp. T177-T182.

    http://www.pulpandpapercanada.com/paptac/pdfs/nov07/machinedesign2.pdf

  • Anish Philip 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.
    Anish Philip · University of Eastern Finland

    Can someone help me finding the JCPDS pattern for my sample of Au nano-particles on silica matrix?

  • F. Caballero-Briones added an answer:
    Can anyone tell me how to clean FTO coated glass for electrochemical deposition? Can we use piranha cleaning procedure for FTO cleaning?
    Cleaning of Fluorine doped Tin Oxide (FTO) Glass for Electrochemical deposition.
    F. Caballero-Briones · National Polytechnic Institute-CICATA Altamira

    I disagree on using RCA process or any solvent to clean it, mostly because it leaves adsorbed traces that would cause spots of non deposition. RCA works fine when used in vacuum processes. We had that problem in anodizing Cu. KOH etching is very suitable as O. Niitso anmd T. Deuschmann mention, it activates the surface and produces more adherent and uniform deposits. It is possible to pass some 6-7 Ampers thru the FTO (or ITO) substrate in the 1M KOH solution at room temperature during 2 minutes to further activate the surface.

  • Qazale Sadr Manuchehri added an answer:
    How to determine the magnetic properties of sol-gel derived Fe2O3-TiO2 nanocomposites?
    I have synthesized the above nanocomposites but we are trying to know the magnetic properties and couldnt find any easiest method.
    Please suggest some from your experience!
    Qazale Sadr Manuchehri · Islamic Azad University

    Take hysteresis curve by Vibration sample magnetometer (VSM).

  • James B Oliver added an answer:
    Is there any free software for the analysis of multi layer thin film?

    Rocking Curve ,GIXD

    James B Oliver · University of Rochester

    I would also add Open Filters - it is an open source thin-film design program written by a former student at Ecole Polytechnique.  Available for free download.

  • Saeed Hasani added an answer:
    What is the range of coercivity for hard and soft magnetic material?

    I have studied the magnetic property of the ni based film. its coercivity is 709G.Is it hard or soft magnetic material? Is there any range for hard and soft magentic material? I have attached the hysteresis loop. I don't know which type of magnetic material it is. For the super paramagnetic material how the hysteresis look like. please any one answer my question.

    Saeed Hasani · Isfahan University of Technology

    Dear Raji,

    pls go to the below link and click on the cover of book and download it.

    With Bests

    http://libgen.org/book/index.php?md5=edd5db76a7667474ddcc280ee0a85b91

  • William A. Rigdon added an answer:
    Can I effectively get a fine film coating of carbon nanotube?

    i have problem in coating glass discs with carbon nanotube. at the begining i functionalized the glass disc with APTES and the next step i am tring to attach the carboxylated CNT to the APTES surface with the conjugation of  N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride . and to do that i dipreased the CNT with ethanol until it change to grey uniform liquid then added the conjugation factor (N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride) then immerse the CNT in that solution for three hours to give the enough time for the reaction ,but what i got was after emmerse it in few minutes the CNT start to glomurlate in areas and leave the other surface areas of glass empty, i tried other method by put drops of (CNT +ethanol)on the surface and i got the same result. i am wonder if somebody can help to perform thin and uniform CNt coating?

  • E. A. Skryleva added an answer:
    Atomic ration calculation (O to Ti stoichiometry calculation) using core emissions data from XPS and SDP software?

    Hi everyone,

    For a part of my study on TiO2 nanoparticles, I need to perform atomic ration calculation (O to Ti stoichiometry calculation) using core emissions data from XPS. I have access to SDP software and was wondering if anyone possibly knows how to perform such analysis. Additionally, I have heard that the stoichiometric analysis needs to use the cross section factor for Ti and O to correct the integrated area from XPS data, and how can I get the value of these factors? It can be very tricky.

    So, any help to show me how this can be performed and how to get reliable results is greatly appreciated.

    Thanks indeed.

    E. A. Skryleva · National University of Science and Technology MISIS

    1. All details of the quantitative analysis are well represented in the International standard ISO 18118 “Surface chemical analysis – Auger electron spectroscopy and X-ray photoelectron spectroscopy – Guide to the use of experimentally determined relative sensitivity factors for the quantitative analysis of homogeneous materials”
    2. Usually the O1s spectrum of TiOx, 1,8<x<2,0, contains two components: peak 1 BE = (529,9 - 530,0) eV from oxide and peak 2 BE = (531,5 – 532,0) eV from adsorbed oxygen. It is necessary to measure only the integrated intensity of the first peak.
    3. Don’t use ion etching of TiO2 samples. Oxide reduction occurs even at very low energies, 100-200 eV. In addition to the Ti2p spectrum of TiO2, BE Ti2p3/2 = 458,5 – 458,8 eV, the spectra of the Ti suboxides will be observed at lower energies: 457,0 – 457,7 eV from Ti2O3 and 455,2 – 455,3 from TiO

  • Etienne Schacht added an answer:
    Does Glyceryl oleate have plasticization property in preparing films or not?

    I am using Glycerly oleate with PEG 400  of amount 0.1 mg and 2.5 mg per strips weighing 200 mg contains 78 mg of pullulan but it shows elongation , probably due to over plasticization. What is the solution ?How to reduce elongation

    Etienne Schacht · Ghent University

    An additive acts as plasticizer if it is soluble in the polymer. To check on this run a DSC analysis and see if addition of the product you expect to be plasticizer lowers the Tg of the polymer...

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