Thin film (Physics)

Potential applications of diamond-like carbon (DLC) coatings range from precision tools and biomedical implants to micro mechanical devices and engine components. Where uniform coatings are required on substrates with complex geometries, plasma enhanced chemical vapour deposition (PECVD) is often a preferred deposition method. As a non-line of sight process, the geometry of the substrate is often considered negligible. For this reason analysis of PECVD coatings, such as amorphous carbon, has mostly been concerned with reactor deposition variables, such as bias voltage, pressure and gas ratios. Samples are therefore usually prepared and positioned to minimise the influence of other variables. By depositing nominally similar DLC films on silicon samples positioned horizontally and vertically on the reactor cathode plate it was possible to examine the variations in the coating characteristics and mechanical properties that occur due to the geometry of the substrate being coated. Topographic measurements and analysis of bonding structures revealed significant heterogeneity in the coatings. Electron microscopy showed variation in surface structure as well as thickness disparities of up to 50% in the vertical sample. Atomic force microscopy showed roughness, Ra, varied from 0.37 nm to 15.4 nm between samples. Raman spectroscopy highlighted variations in the sp2/sp3 bonding ratios whilst micro wear tests demonstrated how these variations reduce the critical load performance. These effects are explained in terms of the deposition mechanisms involved and are related to variation in deposition species and geometrical field enhancements within the deposition chamber. Improved understanding of these local variations will aid in the optimization of coatings for complex substrate geometries.

Effect of [Cu/In] ratio on the optical properties of CuInS 2 thin films prepared by chemical spray pyrolysis on glass slides at 300 o C was studied. The optical characteristics of the prepared thin films have been investigated using UV-VIS spectrophotometer in the wavelength range (300-1100 nm). The films have a direct allow electronic transition with optical energy gap (E g ) decreased from 1.51 eV to 1.30 eV with increasing of [Cu/In] ratio and as well as we notice that films have different behavior when annealed the films in the temperature 100 o C (1h,2h), 200 o C (1h,2h) for [Cu/In]=1.4 . Also the extinction coefficient (k), refractive index (n) and the real and imaginary dielectric constants (ε 1 , ε 2 ) have been investigated.

In recent years the structures of thin layers have been widely studied, because of their properties that are unattainable in bulk materials. The aim of this paper is to present the dislocation energy per unit length of the Sn Ag thin films deposited on Glass. Dislocation energy per unit length of a 20 nanometer Sn Ag thin films with 10 and 90 percents of Ag and Sn , respectively, have been calculated using low angle incident x-ray scattering. Results obtained by the proposed experimental test, is then compared with the theoretical analysis data. The dislocation energy's per unit length of the Sn Ag thin films at temperatures of 25, 325, 525 and 625 oC, has been theoretically obtained equals to 1.3679 (nm)2Gpa, 2.138(nm)2Gpa, 1.7551(nm)2Gpa and 1.8959(nm)2Gpa, respectively.

Despite Cu 2 ZnSnS 4 (CZTS) is a potential candidate for solar cell applications, so far, low efficiency values have been reported. In particular, for spray-deposited CZTS, efficiencies lower than 2% are commonly achieved. It is well known that one of the most important parameters governing solar cell performance is minority carrier diffusion length (L n). In this work, CZTS thin film solar cells with different composi-tional ratios are fabricated in order to study its impact on L n values. The L n parameter is calculated for sprayed-CZTS layers using external quantum efficiency measurements in conjunction with optical absorption coefficient versus wavelength measurements – for the first time. Values in the range of 0.11–0.17 lm are obtained emphasizing the need for improving sprayed-CZTS crystalline quality.

A superluminal quantum-vortex model of the electron and the positron is produced from a superluminal double-helix model of the photon during electron-positron pair production. The two oppositely-charged (with Q = ±e sqrt (2/α) = 16.6e) open-helix spin-½ half-photons compose the double-helix photon. These half-photons separate and curl up their separated superluminal single-helical trajectories to form an electrically-charged superluminal closed-helix spin-½ quantum-vortex electron model and a corresponding positron model. The helical radius and the Dirac equation's zitterbewegung angular frequency of the quantum vortex electron and positron models equal the helical radius and zitterbewegung angular frequency of the two spin-½ half-photons, each of energy E = mc^2 , that composed the double-helix photon model of energy E = 2mc^2 from which the electron and positron models were produced. The photon and electron models are also compatible when a photon of energy E > 2mc^2 produces a relativistic electron-positron pair. Implications of the quantum vortex electron model for electron stability are discussed.

This review introduces relevant nanoscale thermal transport processes that impact thermal abatement in power electronics applications. Specifically, we highlight the importance of nanoscale thermal transport mechanisms at each layer in material hierarchies that make up modern electronic devices. This includes those mechanisms that impact thermal transport through: (1) substrates, (2) interfaces and 2D materials, and (3) heat spreading materials. For each material layer, we provide examples of recent works that (1) demonstrate improvements in thermal performance and/or (2) improve our understanding of the relevance of nanoscale thermal transport across material junctions. We end our discussion by highlighting several additional applications that have benefited from a consideration of nanoscale thermal transport phenomena, including radio frequency (RF) electronics and neuromorphic computing.

CURRICULAM VIATE (CV)
Dr Syed Arshad Hussain
Assistant Professor (stage-III)
Department of Physics
Tripura University (A Central University)
Suryamaninagar – 799022
Tripura, India
Email: [email protected] / [email protected]
Website: https://sahussaintu.wordpress.com/
http://www.tripurauniv.in/index.php/for-faculties?id=198

This review on perovskite (ABO3) materials focuses primarily on ferroelectric films used in devices for charge storage such as Pb(Zr, Ti)O3 (PZT) for non-volatile ferroelectric random access memory (FeRAM) and high dielectric constant materials containing (Ba, Sr)TiO3 (BST), but it also emphasizes general principles on the integration of electroceramics in devices and microelectro mechanical systems (MEMS). The number of papers reported in the literature on ferroelectrics has expanded greatly in the past 20 years, but classical reliability problems in ferroelectric devices remain. Greater emphasis is needed on understanding key mechanisms which result in degradation of ferroelectric materials’ electrical characteristics in devices over time and with usage particularly between the ferroelectric film and electrode interface. In addition, better quantification of numerical measures of thin films are needed in order to more closely relate the process conditions to the materials characteristics and the resultant electrical properties. Furthermore, materials reliability and analysis of complex systems is a topic that needs further consideration when researching/working with ferroelectric devices. Finally, problems with materials reliability in ferroelectric devices are in need of further detailed investigation by researching and understanding the mechanisms which are the root causes of ferroelectric polarization losses in actual devices.

Ga katkılı ve katkısız ZnO filmler sol-gel spin kaplama yöntemiyle cam
altlıklar üzerine kaplanmıştır. Filmler farklı katkılama konsantrasyonları ve farklı ısıl
işlem sıcaklıklarında elde edilmiştir. Çalışmada çinko kaynağı olarak çinko asetat
(ZnAc) kullanılmıştır. Çözücü olarak 2-propanol kullanılmıştır. ZnAc 2-propanol
içinde çözüldükten sonra arzu edilen katkılamayı elde edebilmek için çözeltiye
değişik kütlelerde Galyum(III)Nitrat Hidrat eklenmiştir. Filmler katkısız, %0,05-
%0,1 ve %0,2 Ga katkılı olmak üzere dört farklı katkılama konsantrasyonunda elde
edilmiştir. Elde edilen çözeltiler, cam altlık üzerine spin kaplayıcı ile kaplanmıştır.
Her film 10 kez döndürme işlemine tabi tutulmuştur. Kaplama esnasında her
döndürme işleminden sonra filmler 250 °C’de 1 dakika ısıl işleme tabi tutulmuştur.
En son elde edilen filmler 500–550 ve 600 °C olmak üzere üç farklı son ısıl işleme
tabi tutulmuştur.
Filmlerin optik ve mikroyapısal özelliklerini incelemek amacıyla X ışını
kırınımı (XRD), UV-Vis. fotospektrometre ve Taramalı elektron mikroskobu (SEM)
ölçümleri yapılmıştır.
Yapılan ölçümler sonucunda katkılama konsantrasyonu ve fırınlama sıcaklığı
arttıkça genel olarak filmlerde (002) düzlemi XRD pik şiddetlerinde artma olurken
(101) düzleminin pik şiddetinde azalma gözlenmiştir. Katkılama yükseldikçe bazı
filmlerin örgü parametrelerinde yükselme gözlenmiştir. Filmlerin SEM fotoğrafları
incelendiğinde bütün filmlerin polikristal yapıda olduğu görülmektedir. 550 °C’de ve
600 °C’de elde edilen filmlerde nano boyuttaki boşlukların birleşmesi ile çatlaklar
oluştuğu gözlenmiştir. Filmlerin büyük bir çoğunluğu görünür bölgede %70’in
üzerinde geçirgenlik göstermiştir. Filmlerin optik geçirgenliği genel olarak artan ısıl
işlem sıcaklığı ile artış göstermiştir.

In the presented study, (Ni, Mg) co-doped CdS thin films are synthetized using the spin coating method. The Mg incorporation effect on the structural, opto-electrical quality of Cd 0.98 Ni 0.02 S with different Mg concentrations (0 wt%, 1wt.%, 3wt, and 5wt.%) are investigated. A polycrystalline nature with a cubic structure oriented to (1 1 1) plane was confirmed by the DRX technique, and the incorporation of Mg in Cd 0.98 Ni 0.02 S causes an increase of the grain size. The SEM study exhibits a surface of deposited films is dense and the EDS spectra confirmed the existence of the doped elements. The optical properties show that the doping with 3 at.% of Mg presents the maximum each a value of 90% in visible range, with an increasing in the gap energy from 2.42 eV to 2.49 eV corresponding to increasing of Mg concentration. And also optical parameters were investigated such as α, k, n, ε r , ε i , tan δ, σ. The electrical resistivity and conductivity measurements are carried using the four points probe, we find that the electrical resistivity decreases from the 7.30×10 3 (Ohm. cm) to 4.28× 10 3 (Ohm. cm) while Mg concentration increases from 0 at% to 5 at%.

İnce film üretim teknikleri
Kopartma (Sputtering) yöntemi
Kopartma (Sputtering) sisteminin temel bileşenleri
Kopartma (Sputtering) yönteminin parametreleri
Kopartma (Sputtering) sisteminin çalışma prensibi
Kopartma (Sputtering) yönteminin uygulandığı sistemler
Magnetron kopartma (sputtering) sistemi
DC/RF (diyot) kopartma (sputtering) sistemi
Triyod kopartma (sputtering) sistemi
İyon Demeti kopartma (sputtering) Sistemi
Magnetron ve magnetron olmayan kopartma sistemleri arasındaki fark
Kullanılan gazlar
Uygulama alanları
Avantajları
Dezavantajları
Özet
Kaynaklar
Teşekkür

Bu çalışmada V3O7 ve V8O15 ince filmler sol-jel daldırma yöntemiyle cam ve p-Si yarıiletken yüzeyler üzerine kaplanmış; AFM ile yüzey yapısı araştırılmış, XRD ile filmlerin polikristal yönelmeleri ve kristal yapıları incelenmiştir. EDX ile filim muhtevası araştırılmış. UV-VIS ölçümleri ile optik özellikleri araştırılmıştır. Elde edilen filmlerden Al/VOx /p-Si/Al MOS yapılar oluşturularak akım-gerilim, kapasite-gerilim-frekans yöntemleriyle elektriksel ve fiziksel özellikler incelenmiştir.
İnce filmleri elde etmek için %99 saflıkta V2O5 tozu, HCl, HNO3, H2O2 çözücülerinin farklı birleşimleri içinde çözünerek homojen çözeltiler elde edilmiş ve kaplanacak olan cam veya p-Si yüzey bu çözelti içerisine 600 um/s hızla daldırılmıştır. Bu şekilde kaplanan yüzey öncelikle 300 derece 5 dakika tavlama işlemine tabi tutulmuş 10. kattan sonra 400 ile 500 derece arasında değişen sıcaklıkta 1 saat tavlamaya tabi tutulmuştur.
MOS yapılar elde etmek için p-Si üzerine elde edilen filmlerin bir tarafı buharlaştırma yöntemiyle Al kaplanmış, diğer tarafı yine buharlaştırma yöntemiyle delikli maske kullanılarak Al kaplanmıştır.

In this study, the coating technique was used to prepare thin layers of nickel and aluminum-codoped tin oxide (SnO 2 : Ni; Al). This study is aimed at exploring the influence of aluminum (Al) dopant on the structural, optical, and electrical properties of the elaborated films. X-ray diffraction (XRD) studies discovered that all deposited films (Ni-doped and Al-Ni-codoped SnO 2) were polycrystalline with tetragonal (quadratic) structure and exhibited [110] preferential orientation. The optical measurements exposed that all prepared films have presented good transparency. The transmittance of Ni-Al-codoped SnO 2 thin films in the visible and near-infrared regions varied between 80% and 90%; this was dependent on the concentration of dopant. The band gap was determined via the equation related to the absorption coefficient. It was deduced that the optical band gap values of thin films gradually decreased from 4.084 eV to 3.991 eV, as an effect of Al content. In addition, it was concluded that the thickness values of the films pass from 571.374 nm to 694.036 nm as an effect of Al content. Moreover, the extinction coefficient decreases with the wavelength in the UV region and then varies slightly towards longer wavelengths. Moreover, the electrical resistivity was determined using the four-point probe; it was determined that the electrical resistivity decreases from 1:35 × 10 3 ðΩ • cmÞ to 0:14 × 10 3 ðΩ • cmÞ with aluminum concentration increasing from 0 at. % to 7 at. %. The elaborated films of SnO 2 codoped with Ni and Al present were highly transparent; therefore, these thin layers look promising in the use of the window layer in PV solar cells.

SnO2 thin films have been deposited onto glass substrates by spray pyrolysis technique. Tin chloride
and copper nitrate were used as source of Sn and Cu respectively. The structural, optical and
electrical properties of SnO2 films have been investigated as a function of Cu-doping (1~8 wt. %).
The SEM micrographs of film show uniform deposition and EDX results show the stoichiometry and
elemental composition of the films (viz. Cu, Sn and O, etc.). The optical transmission was found to
increase from 71 % to 79 % for 200 nm thickness with the addition of Cu up to 4 % and then
decreased for higher concentration of copper doping. The optical band gap for pure SnO2 film was
found 3.75 eV. Due to Cu doping, the band gap was shifted to lower energies and then increased with
further increasing of doping concentrations. X-ray diffraction studies show the polycrystalline nature
of the films with preferential orientation along the (101) planes and an average grain size of 7.244 Å.
The resistivity of SnO2 films was found to decrease initially from 4.5095×10−4 Ωm to 1.1395× 10−4
Ωm. The experimental results discussed the suitability of this material for using as transparent and
conducting window materials in solar cells.

The heteroepitaxial growth of the new ternary, group-IV, semiconductor material, Si1-x-yGexCy on Si(100), has been investigated. The epitaxial quality of Si1-x-yGexCy is found to be inferior to that of Si1-xGex with similar Si/Ge concentration ratio, grown under identical conditions, and the quality deteriorates with increasing C fraction. Also, the surface roughness, as studied by tapping mode atomic force microscopy, increases with increasing C fraction as well as with increasing Ge fraction, suggesting a transition from Frank-van der Merve to Stranski-Krastanov type growth. We suggest that the very large mismatch between the average bond length in the Si1-x-yGexCy material, as determined by Vegard's law, and the equilibrium Si-C bond length, weakens the Si-C bonds and reduces the elastic range of the material, thus lowering the barrier for dislocation and stacking fault formation. The change in elasticity may also be responsible for the change in growth morphology, either directly by a lowered barrier for island formation or indirectly through the formation of defects. A decrease in Ge incorporation in the Si1-x-yGexCy films with increasing C incorporation suggests a repulsive Ge-C interaction. Moreover, we observe a C-rich, Ge-deficient precursor phase to SiC precipitates at a growth temperature of 560 degrees C, whereas at 450 degrees C no such phase can be observed. The temperature dependence of the precursor formation is consistent with C bulk diffusion. Infrared absorption measurements cannot be used to detect the precursor phase. Finally, the onset of epitaxial breakdown is discussed and an accurate and independent determination of the C fraction and its substitutionality is emphasized. (

We investigate a quantum well that consists of a thin topological insulator sandwiched between two trivial insulators. More specifically, we consider smooth interfaces between these different types of materials such that the interfaces host not only the chiral interface states, whose existence is dictated by the bulk-edge correspondence, but also massive Volkov-Pankratov states. We investigate possible hybridization between these interface states as a function of the width of the topological material and of the characteristic interface size. Most saliently, we find a strong qualitative difference between an extremely weak effect on the chiral interface states and a more common hybridization of the massive Volkov-Pankratov states that can be easily understood in terms of quantum tunneling in the framework of the model of a (Dirac) quantum well we introduce here.

Reflectance spectra calculations of double and multi-layer antireflection coating (ARC) structures based on Fresnel equations were studied in this work. A detailed explanation of Fresnel equations was presented with different polarization of incoming light for multi-layer antireflection coatings for solar cell applications. TiO2/SiNx, MgF2/ZnS thin film stacks for double layer ARC and SiO2/Al2O3/TiO2, MgF2/SiO2/TiO2 thin film stacks for multi-layer ARC were studied. Transfer matrix method and PC1D simulation software were used additionally to simulate crystalline silicon solar cells with considered double and multi-layer ARC films on their front surface with calculated thicknesses. Average reflectance (400-1100 nm) of silicon surface by Fresnel equations with triple layer ARC was around 2.72%. Solar cell performances with each ARC structure were compared to evaluate the achieved output of reflectance of investigated thin films. Simulated short circuit current density of solar cells with tri-layer ARC was 39.71 mA/cm 2 , was significantly higher than that of the ARC-free solar cells resulting in an efficiency of 19.1%.

While the standard interpretation treats CdS/CdTe, CdS/Cu(In,Ga)Se2(CIGSe) and CdS/kesterites as p-n junctions, some recent reports suggest these solar cells operate rather as a Metal-Insulator-Semiconductor (MIS) structure. In this paper, we report results about the dependence of electrical, optical, morphological and structural properties of CBD-CdS on growth conditions in order to obtain the best layers to be used in solar cells according to the MIS model. In particular, CBD-CdS thin films were synthesized by changing the complexing agents in the bath solution, the Cd source and the nominal S/Cd ratio. In order to study the impact of the different CdS deposition approaches, CIGSe and CZTSe solar cells were processed. The influence of CdS:Cu as well as Cd sources such as Cd(NO3)2 and CdSO4 on solar cell electrical parameters is studied.

Broad and low-intensity Raman peaks are usually expected from nanocrystal-line thin semiconductor films. The inherently weak Raman scattering phenomenon can be further deteriorated by unwanted background signals preventing the successful Raman analysis of an analyte. In this study, the resonant and surface-enhanced Raman scattering techniques were combined to detect CuO and Cu2O phases in the partially oxidized nanocrystalline copper film that were otherwise undetectable. Heat treatment resulted in increased oxidation and phase transition from multiphase to single CuO phase that was in situ observed by temperature-dependent Raman measurements.  Detailed understanding of the film properties and substrate interaction was made by using several characterization techniques.

Ternary thin films of Iron Copper Sulphide (FeCuS) have been grown and characterized. Optical, compositional, surface microstructure and structural characterization of the deposited films were carried out. Absorbance spectra data of the films were obtained using a Janway 6405 UV-VIS spectrophotometer, absorbance of the films were found to be high in UV and low in VIS – NIR region, while the transmittances were low in UV region and high in VIS – NIR regions. Elemental composition of
the films were done using Skyray XRF Machine, EDX Pocket III, model P530. The machine was used to determine the percentage of each transition element present in the films. The surface microstructures of the films were characterized using Olympus Microscope at 100X magni fication. XRD analysis of the
films was carried out using Enhance Mini Material Analyzer (EMMA) X – Ray Diffractometer Machine, the as - deposited FeCuS thin film was found to have tetragonal structure. The lattice constants obtained are a =10.585 Å, b = 10.585 Å and c = 5.383 Å. The crystallite size of the film was calculated at Cu Kα
wavelength of 1.5406 Å and the calculated grain size was found to be 0.389 nm (3.589 Å).  The optical absorption study reveals that FeCuS thin film has a bandgap of 2.40eV and a refractive index range of 2.00 to 2.70 at 400nm. The reflectance of the deposited films was found to be generally low.

Lead-free Bi 0.5 Na 0.5 TiO 3 (BNT)-Bi 0.5 K 0.5 TiO 3 (BKT)-BaTiO 3 (BT) piezoelectric thin films with compositions near the morphotropic phase boundary (MPB) were deposited by metal-organic solution deposition on Pt/Ti/SiO 2 /Si (1 0 0) substrates. The compositional dependences of their microstructure and ferroelectric/piezoelectric properties were investigated. The results indicated that all the thin films have a single-phase perovskite structure and show outstanding electrical properties at room temperature. We found that the thin film with a composition of 0.884BNT-0.08BKT-0.036BT showed the best structural and electrical properties, with a dielectric constant, remnant polarization, and effective piezoelectric constant of $638, $27 lC/cm 2 and $79 pC/N, respectively. We suggest that these superior properties are due to this sample's high degree of alignment of ferroelectric domains in the MPB region and largest grain size.

Au/graphene oxide (GO)-doped PrBaCoO nanoceramic/n-Si capacitors were fabricated and their admittance measurements were carried out between 1 kHz and 1 MHz at room temperature. Experimental results showed that the capacitance (C) and conductance (G/w) values are strong functions of frequency and applied bias voltage. C–V plot revealed two distinctive peaks at low frequencies which are located at about 0 and 2 V, such that the first peak disappears towards high frequencies. The energy density distribution profile of the interface/surface states (D it / N ss) and their relaxation time (s) and capture cross section (r p) of the sample were obtained by using the admittance method. In addition, the voltage-dependent profile of N ss and resistance were obtained by using low–high frequency capacitance and Nicollian-Brews method, respectively, and they also reveal two distinctive peaks, respectively. Two peaks' behavior in the forward bias C–V, N ss –V and R i –V plots confirmed the existence of two different localized regions of N ss between Si and interfacial layer. The series resistance (R s) of the device decreased with increasing frequency from 175 X at 1 kHz to 72 X at 1 MHz. As a result, the mean value of D it was found about 5 9 10 13 eV-1 cm-2 which is reasonable for an electronic device.

Presented here is a patent in the Bulgarian register of inventions (Reg. № 41177/1978), written in Bulgarian. The patent relates to uniform deposition of semiconducting and insulating thin films in cold gas plasma. Various flat substrates can be used, semiconductor ones in particular. The claims relate to a specific configuration of the reactor chamber by which uniformity of the (static part of) gas plasma is achieved. That feature results in improved uniformity of the thus deposited thin films, as compared to the one achieved by the existing systems. The application of this method is demonstrated on Si3N4 and SiO2 thin layers deposited onto Silicon wafers, aimed for the mass production of MOS IC’s (Metal-Oxide-Semiconductor Integrated Circuits).

The invention described features one claim. The description is supported by two drawings.

CuInSe 2 is considered as a striking semiconductor for second generation solar cells. An investigation of optical properties of CuInSe 2 thin films is essential to evaluate its perfectibility as high efficiency solar cells. The films were fabricated by thermal co-evaporation technique. For this experiment, a shimadzu spectrophotometer of model number 1201 is used. The optical properties of these films are determined for the wavelength range 350 nm -1100 nm. From the experiment it is evident that the reflectance and transmittance of the films are negligible in comparison to the absorption of these films. The high absorption coefficient of the order of 104/cm of the film material also supports this. The band gap of the CuInSe 2 films was evaluated to be 1.1 eV. From XRD and EDAX analysis it is evident that CuInSe 2 films are polycrystalline in nature having ideal stoichiometric composition.

The differences between amorphous and glassy state are discussed and the methods of their preparation reviewed. The role of crystallization during fast cooling is analyzed and nucleation-growth process is shown in two attitude models, which characterization are depicted on DTA curves. Specificity of non- and nano-crystalline metallic glasses is revealed.

Strong electrophilic natured acetaldehyde present in various food and beverages damages genetic material and induces diseases like atherosclerosis. Detection and quanti fi cation of such a carcinogen poses a major challenge. In this context, a novel room temperature acetaldehyde sensor made up of hierarchical ZnO nanostructures and prepared by a simple and template-free method has been reported. ZnO nanostructures were grown on glass substrates by a chemical spray pyrolysis technique at the substrate temperature of 523 K. Di ff erent nanostructures, namely tiny nanoplatelets, branched nanorods and thicker nanoplatelets, were formed by an annealing process. The crystal structures, morphologies and optical absorbances of the hierarchical ZnO nanostructures were investigated by X-ray di ff raction (XRD), field emission scanning electron microscopy (FE-SEM) and UV-vis spectrophotometry, respectively. The branched nanorods showed an excellent sensing response towards 20 to 500 ppm of acetaldehyde
vapour. The role of high density junctions of the branched ZnO architecture in enhancing the vapour sensing performance has been highlighted. The observed selectivity, range of detection and stability of the branched ZnO nanorods have proven their potential as a sensing element for the detection of acetaldehyde.

BaCuChF (Ch = S, Se, Te) materials are chalcogen-based transparent conductors with wide optical band gaps (2.9 – 3.5 eV) and a high concentration of free holes (10¹⁸ – 10²⁰ cm⁻³) caused by the presence of copper vacancies. Chalcogen vacancies compensate copper vacancies in these materials, setting the Fermi level close to the valence band maximum. BaCuChF thin film solid solutions prepared by pulsed laser deposition (PLD) have tunable properties, such as lattice constants, conductivity and optical band gaps. BaCuSF and BaCuSeF materials also feature room-temperature stable 3D excitons with spin-orbit-split levels. BaCuTeF has forbidden lowest-energy optical transitions which extends its transparency range. BaCuChF surfaces oxidize when exposed to air, but can be protected using Ch capping layers. Polycrystalline BaCuSeF thin films have a 4.85 eV work function, a 0.11 eV hole injection barrier into ZnPc, and 0.00 eV valence band offset with ZnTe. BaCuSeF should have s similar band offset and similar interfacial properties with CdTe and Cu(InGa)Se₂, and BaCuSF should have no valence band offset with Cu₂ZnSnS₄, according to the transitivity rule. Therefore, BaCuSeF is suitable for applications as a p-layer in organic light-emitting diodes, p-i-n double-heterojunction and tandem chalcogenide solar cells.

Spontaneous hierarchical self-organization of nanometre-scale subunits into higher-level complex structures is ubiquitous in nature. The creation of synthetic nanomaterials that mimic the self-organization of complex superstructures commonly seen in biomolecules has proved challenging due to the lack of biomolecule-like building blocks that feature versatile, programmable interactions to render structural complexity. In this study, highly aligned structures are obtained from an organic–inorganic mesophase composed of monodisperse Cd37S18 magic-size cluster building blocks. Impressively, structural alignment spans over six orders of magnitude in length scale: nanoscale magic-size clusters arrange into a hexagonal geometry organized inside micrometre-sized filaments; self-assembly of these filaments leads to fibres that then organize into uniform arrays of centimetre-scale bands with well-defined surface periodicity. Enhanced patterning can be achieved by controlling processing conditions, resulting in bullseye and ‘zigzag’ stacking patterns with periodicity in two directions. Overall, we demonstrate that colloidal nanomaterials can exhibit a high level of self-organization behaviour at macroscopic-length scales.

CdS thin films were deposited by vacuum thermal evaporation technique on Fluorine-doped Tin Oxide glass substrates at different substrate temperatures ranging from 50 to 250 • C. Post deposition heat-treated thin films were characterized for optical, structural, morphological and electrical properties to study the dependence substrate temperature. The optical bandgap was found in the range of 2.42-2.46 eV. Crystallite size, microstrain, phase distribution, and lattice parameters were calculated using x-ray diffractogram profile fit, Rietveld and Pawley refinement techniques. Best electrical properties of photoelectrochemical cells were observed for the films grown at a substrate temperature of 175 • C. CdS/CdTe full cells were fabricated using thermal evaporation technique and the highest efficiency of 3.76% and highest external quantum efficiency of 70% were observed for the CdS thin film grown at a substrate temperature of 175 • C and the variation was confirmed with SCAPS-1D simulation.

Conventional crystalline silicon-based solar cells still dominate in the market even though several types of photovoltaics (PVs) have been developed. The price per watt generated by typical crystalline silicon-based solar cells has notably dropped in the recent past while the efficiencies have been improved up to a reasonable level. However, crystalline silicon-based solar cells need high-temperature and high-vacuum facilities for manufacturing and are still expensive to compete with fossil fuels. Dye-sensitized solar cells (DSSCs) are being studied as a promising alternative to crystalline silicon-based solar cells since they are easy to fabricate, cheap to manufacture and possess satisfactory efficiencies. But further studies are essentially needed to enhance the overall performance of DSSCs and to reduce the manufacturing cost so as to make them more commercially viable. Current studies are mainly focused on cost reduction, improvement of performance, and development of suitable electrolytes.
Even though Pt is an expensive material, it is the most widely used counter electrode material in DSSCs because of its high catalytic effect and electrical conductivity. Therefore, carbon-based materials such as carbon black, carbon nanotubes, activated carbon, graphite, and graphene which are abundant, low cost compared to Pt while showing high catalytic activity and electrical conductivity have been studied as counter electrode materials to replace Pt.
Under this project, development of multilayer graphene-based counter electrodes for DSSCs based on TiO2 working electrodes is explained. First, a viscous paste of multilayer graphene was prepared by mixing multilayer graphene and an organic binder with water, and the paste was screen printed on cleaned FTO glass substrates. Then prepared counter electrodes were annealed in a furnace. The graphene to binder mass ratio in the paste, annealing temperature, and the film thickness of multilayer graphene-based CEs were optimized so as to optimize the overall efficiency of DSSCs based on multilayer graphene-based counter electrodes and TiO2 working electrodes. In this project, the maximum efficiency of 6.89 % was achieved with the multilayer graphene-based counter electrodes while the maximum efficiency achieved with the platinum counter electrodes under the same conditions was 8.64 %.

Azopolymers are well known organic materials for polarization holographic recording due to the induced anisotropy under illumination with polarized light. They possess all the desirable characteristics of the known polarization-sensitive materials, as high sensitivity and reversibility, but excel them substantially in the magnitude of the photoinduced birefringence. This makes possible to record reversible polarization gratings with high diffraction efficiency. In this paper results of experimental investigations on the reversibility properties of birefringence photoinduced in azopolymers are reported, depending on the conditions of subsequent optical and thermal treatment. Thin films of different polymers were prepared in order to examine the kinetics of multiple recording and erasure of birefringence in different types of azopolymers. The reversibility of the polarization recording has been studied using two different method of erasure-by increased temperature and on illumination with circularly polarized light.

TECHNICAL FIELD - This application relates to the field of coatings that prevent fogging on solid surfaces without altering the characteristics of the covered surface. The coatings may be used on devices and equipment for sports and recreation, the medical field, military and industrial safety
applications. Such devices and equipment include windows and mirrors of automobiles, motorcycles, boats, airplanes, and trains. In industrial and instrumentation application: protective windows, domes, and lenses of gauges, dials, meters. In medical applications: intraocular lenses, endoscopic/laparoscopic lenses, protective eyewear, contact lenses for visual correction, medical implants, surfaces, and medical and surgical tools.
BACKGROUND
The problem of condensation with fogging: Hydrophobic versus hydrophilic surfaces. Protective eyewear, glasses, sunglasses, swimming goggles, diving goggles, helmet visors, windshields, intraocular lenses, medical scopes, and high-precision instrumentation are just several applications where visual distortion due to fogging with condensation poses a problem.
Control of fogging due to condensation on polymer and glass surfaces has seen development, testing and patenting of solutions for a broad spectrum of optical, vision, visor, goggle and lens materials, including optical glasses, borosilicate glass, polycarbonates, tinted thin film coatings, and other polymers for athletic visor and vision-wear. These can require optimization of the robustness and resiliency to create permanent anti-fog coatings, and optimization of adhesion on polycarbonates and surfaces with difficult geometries such as very high curvature. Therefore, anti-fog technologies and their applications have to be conceived and optimized by
adapting to a broad range of specifications for use, use duration, etc., and require working directly with a variety of end users to create such adaptability. End users for anti-fog technology include, but were not limited to: surgeons, professional athletes, recreational users, professional safety users, fire-workers, emergency personnel, biohazard handlers, medical and surgical personnel, and instrumentation dials and domes manufacturers.
Control of fogging should be tested using the specific conditions of condensation experienced by each group end users, such as body or outdoor temperatures, and water vapor pressures and various fluids present during use, such as bodily fluids, sweat, blood, skin oils and human tears or fluids produced from machinery. U.S. patent application Ser. No. No. 13/674,307 (hereinafter '307 application) describes an emulsion that physically changes the surface topography so that condensation behavior can be controlled. The result in the '307 application is a hydrophilic surface that manipulates water droplets so that the water droplets form a thin translucent film on the hydrophilic surface. The'307 application describes a  wet anti-fog technology, where the emulsion is applied when the
surface requires an antifogging coating and should not be dried on the surface. When the emulsion of the '307 application is dried, the polymers come out of the solution and precipitate so that the coated surface is no longer optically transparent and fails to maintain optical quality.
Specifically, the emulsion described in the '307 application is optimized for temporary application and for ease of application. The emulsion described in the '307 application was designed for medical applications, including but not limited to vitro-retinal surgery as well as endoscopic and laparoscopic procedures and surgeries. Thus the emulsion described in the '307
application does not permanently coat the surfaces with anti-fog technology. Accordingly, there is need for a dry permanent anti-fog technology that manipulates water so the water droplets form a thin translucent film on a surface rather than produce fogging on the surface while maintaining optical quality. First, the invention consists of permanent anti-fog coatings, including but not limited to their materials components, composition, adaptive formulation and several methods of fabrication.
The permanent anti-fog is referred to as “FogKnox™”. It includes but is not limited to very high quality optical transmission films that are distortion-free, and exhibit a very high degree of transparency. FogKnox™ includes but is not limited to dry, permanent and very highly uniform optical anti-fog coatings, which can be delivered in wet (fluid) or solid from. Both wet and solid form preserve and improve instantaneously visualization on edges of lenses, dials and surfaces and wide-angle lens. Only after drying is the anti-fog a permanent, non-removable solid film. In a separate embodiment, the anti-fog coatings can be made removable for applications where
lenses and devices on which they are applied need to be resurfaced, called KnoxFog™. The antifoam coatings can also be made semi-permanent, so it can be scrubbed, thus removable by scrubbing, detergent washing and/or sonication, for medical applications, and are then called
VitreOx™. Second, the invention includes, for all above mentioned anti-fog coatings, their method of application in large scale, medium scale or small scale manufacturing, via several possible coating processes, adaptive compositions, adjustments of physical properties and surface
preparation procedures, which are disclosed as the second part of the invention. Third, all the above coatings can also be applied on existing, already manufactured optical devices, tools, dials, goggles, vials, bottles and scopes, via the third element of the invention, specific delivery device and its cartridge of anti-fog coatings materials. The delivery device
includes a coating delivery and element to allow for quick drying element attachment to the metered delivery automated mechanism to apply the coating in a few seconds, and let it dry within minutes.

ZnTe thin films were deposited onto soda lime glass substrates by the close space sublimation (CSS) and electron beam evaporation (EBE) techniques under vacuum (as deposited, annealed at 300 uC and Ag doped for 10 min). Structural, morphological, optical and electrical properties of ZnTe films were studied before and after doping. The ZnTe thin films fabricated by EBE technique showed improvement in microstructure, morphology, crystalline orientation and physical parameters such as porosity and density as compared to CSS fabricated thin films. The highest density with very small porosity is observed in EBE fabricated films. The improvement in electrical parameters such as resistivity, mobility, sheet concentration, type of semiconductor (p or n type), bulk concentration and magnetoresistance were observed in EBE fabricated thin films. The highest decrease in electrical resistivity (8?34610 2 V cm) was observed by incorporating Ag dopant via EBE technique. The main purpose of this was a comparative study between EBE and CSS techniques and an improvement in the electrical and optical properties such as electrical conductivity, mobility, sheet resistance/concentration and the band gap of the fabricated thin films. The doping of Ag was performed to observe their effects on morphology, structure, electrical and photovoltaic properties of the as deposited thin films. It was observed that electrical and optical properties of the fabricated films enhanced with dopant and annealing temperature.

The goal of this study is to investigate the effect of carbon incorporation upon thermal oxidation of Si1−x Ge x alloys and its role on strain compensation in Si1−x Ge x alloys. Si1−x Ge x and Si1−x−y Ge x C y alloys on Si(100) are grown by combined ion and molecular beam deposition and are then oxidized at 1000 °C in a dry oxygen ambient for two h. The thickness and the composition of all samples before and after oxidation are measured by Rutherford backscattering spectrometry (RBS) combined with ion channeling at 2.0 MeV and carbon nuclear resonance analysis at 4.3 MeV using 4He++ ions. In agreement with previously reported results of dry oxidation on Si1−x Ge x thin films, 2.0 MeV RBS analysis shows that a layer of SiO2 is formed on the top surface of both Si1−x Ge x and Si1−x−y Ge x C y thin films, while Ge segregates towards the top surface and at the SiO2/Si1−x Ge x and SiO2/Si1−x−y Ge x C y interfaces. However, it is observed for the first time that dry oxidation rates of Si1−x Ge x thin films decrease with increasing Ge fraction x for x≳0.20 and with increasing minimum yield. Ion channeling analysis and strain measurements indicate that the incorporation of C rather than the amount of C itself affects the dry oxidation mechanism because of its strong influence on film strain and crystalline quality. These results are discussed in conjunction with observations by secondary ion mass spectrometry, high resolution transmission electron microscopy, Fourier transform infrared spectrometry, and tapping mode atomic force microscopy.

The inorganic/molecular spinterface is an ideal platform for generating 7 extraordinary spin effects. Understanding and controlling these spin-related effects is 8 mandatory for the exploitation of such interfaces in devices. For this purpose we have 9 investigated the adsorption of α-sexithiophene (α-6T) on La 0.7 Sr 0.3 MnO 3 (LSMO) as one of 10 the prototypical material combinations used in organic spintronic devices. Atomic force 11 microscopy (AFM) confocal photoluminescence X-ray photoelectron spectroscopy and 12 metastable de-excitation spectroscopy unraveled the structure and the electronic 13 configuration of 6T for various surface coverages. This data set allowed the determination 14 of the characteristic features of occupied states: the band diagram and the work function. 15 Finally density functional theory enabled us to establish that the spin polarization in 6T 16 molecular orbitals critically depends on the termination layer of LSMO, showing a 17 substantial effect on the MnO-terminated one only. We believe that this research provides 18 important hints for a comprehensive understanding of spinterface effects in general and 19 offers key suggestions for the optimiziation of 6T/LSMO-based spin devices through the 20 engineering of LSMO termination layer 21 ■ INTRODUCTION 22 Hybridization at the interface between molecular entities and 23 ferromagnetic metals leads to drastic changes of the properties 24 of both layers. 1,2 Notably, an increase of spin polarization of 25 states around the Fermi level, 3 modulation of the magnetic 26 anisotropy, 4 and spin reorientation transitions were observed 27 in ferromagnetic layers as well as the appearance of spin-28 polarized states in the molecular material. 5 Such new hybrid 29 interfaces with unexpected spin functionality, named after the 30 seminal paper by Sanvito as "spinterfaces", 6 act as a key 31 element at the molecular level for engineering the properties 32 and the performance of spin-devices. Among the plethora of 33 spinterfaces, those including half metallic ferromagnetic oxides 34 such as La 0.7 Sr 0.3 MnO 3 (LSMO), are of special interest. LSMO 35 has been coupled to a variety of organic molecules and 36 successfully used in spintronic devices, 7,8 even showing the 37 inversion of the sign of the polarization upon the deposition of 38 an organic molecule. 9 Nonetheless, the variability of the 39 composition of the termination layer of LSMO 10−12 hindered a 40 reliable investigation of its interface with organic molecules. In 41 this paper, we focus on the coupling between a π-conjugated 42 oligothiophene, 6T (sexithiophene), and LSMO, which is one 43 of the first hybrid interfaces used in spin injection devices. 13 44 6T is a rod-like model organic molecule 14 which contains six 45 thiophene rings linked together. It can be easily sublimated in 46 ultra high vacuum (UHV), a prerequisite for the control and 47 reproducibility of interfacial states, and it is also known to form 48 ordered thin layers on solid surfaces. Here, the growth process 49 of 6T on LSMO has been studied by photoemission 50 spectroscopy and metastable helium de-excitation spectrosco-51 py (MDS) to follow the evolution of spectral signatures as a 52 function of coverage. The complementary investigation of 53 morphology by atomic force microscopy (AFM) and 54 molecule−LSMO coupling by confocal microscopy allows a 55 full description of the 6T/LSMO interaction. First-principles 56 calculations based on density functional theory (DFT) help to 57 bridge the gap between the experimental reports on molecular 58 orientation, binding energies, and heights, in addition to the 59 electronic structure of the interface. Our results demonstrate 60 that the interface is characterized by a weak electronic coupling 61 but that, nonetheless, spin polarization extends over the 6T 62 molecule. A spin unbalance between spin up and spin down 63 molecular orbitals is found in case of the organic molecule 64 linked to the Mn−O-terminated LSMO surface. A https://dx.doi.org/10.1021/acs.jpcc.0c09713 J. Phys. Chem. C XXXX, XXX, XXX−XXX kbg00 | ACSJCA | JCA11.2.5208/W Library-x64 | manuscript.3f (R5.0.i5:5005 | 2.

In the present paper, a morphological and optical property of Titanium dioxide (TiO 2 thin film has been studied. A TiO 2 thin film is deposited on glass substrate by physical vapor deposition (PVD) method. The micro structural, optical and electronic properties have been studied by X-ray diffraction (XRD), AFM, U-V absorption and X-ray Absorption Spectroscopy (XAS). The crystallite size of thin film was evaluated using XRD pattern. XRD revealed that TiO 2 existed in the anatase crystalline phase and its crystallite size was 60.77 nm. The morphologies of TiO 2 film were examined by AFM measurement and average grain size and roughness parameter of the films were reported. Using U-V spectra, optical band gap of TiO 2 thin film was calculated and it was found to be 3.2 eV. In the present investigation we observed that the deposited TiO 2 thin films are found to be anatase structure of polycrystalline and crystallite size lies in nanometric range. The XAS measurement of TiO 2 thin film confirms the anatase structure. The fabricated thin film may be used for gas sensing application.

Azopolymers are highly efficient materials, able to register the polarization state of light. They have broad range of applications from diffractive optical elements with unique polarization properties to biophysics. We present a study of birefringence kinetics, induced with five different pump lasers with wavelengths 355, 442, 491, 514 and 532 nm in thin films of widely used amorphous azopolymer PAZO-poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzene sulfon amido]-1,2-ethanediyl, sodium salt]. During the real-time measurement, the value of the photoinduced birefringence (Δn) is determined at 635 nm, using a DPSS laser. When saturation is reached, the spectrum of the birefringence is measured. Our results indicate that the investigated azopolymer can be used for applications in a wide wavelength range.