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A thin film is a surface layer with thickness of a few micrometers. These films have properties much different than that of bulk materials or that of the substrate on which the film is deposited. There are a variety of techniques for thin-film deposition, generally referred to as vapor deposition processes. Depending on the source of the vapors to be deposited, vapor deposition process can be classified as physical vapor deposition (PVD) or chemical vapor deposition (CVD). Among the two, PVD technique is more widely used for thin-film formation. Here, vapors are produced using resistive heating, atomic sputtering, ion plating, magnetron sputtering or lasers, alone or in combination with each other. Most of the PVD processes require a high vacuum. In CVD technique, vapors are obtained from gas, liquid, or solid precursors and involve a chemical reaction for the film formation. Keywords: film formation; thin films; deposition techniques; vacuum deposition; sputter deposition; ion plating; vapors; chemical vapor deposition; plating; chemical solutions; film properties

To identify the generation of various contributions in the electrical response of EuTiO3, a series of pure and doped, morphologically different and crystallographically oriented thin films prepared through RF magnetron sputtering and polycrystalline samples prepared through solid state reaction method have been investigated. Effect of stoichiometry, morphology and crystallographic orientation on the electrical response have been traced. Interestingly, in case of thin films, synthesis in more reducing atmosphere led to an in-plane crystallographic re-orientation from [110] to [100], accompanied by the observation of a prominent intrinsic antiferrodistortive phase transition. At temperatures above the antiferrodistorive phase transition, potential barriers to conduction at grain boundary are found to be directly proportional to the oxygen vacancy concentration, and inversely proportional to the average grain size. The relaxation times obtained from the frequency dependent dielectric response show an anomalous non-monotonic variation with temperature, which arises due to the variation of octahedral tilt angle.

Depending on the sizes of the CdS crystallites and silicon pores, electrical and photoelectrical characteristics of c-Si/porous–Si/CdS heterojunctions prepared by electrochemical deposition and anodization, respectively, are studied. The optimal pore size (10–16 nm) is determined, which provides the maximum photoelectric conversion efficiency (7.71%) of heterojunctions.

The United States needs to add at least 20 GW of peaking capacity to its grid over the next 10 years, led by large-scale projects in California, Texas and Arizona. Of that, about 60% must be installed between 2023 and 2027, meaning that the energy storage industry has more time to build an economic advantage by lowering costs and improving performance to compete with conventional gas peakers. In this paper, we assess the technical feasibility of utility-scale PV plus battery energy storage (PVS) to provide high capacity factors during summer peak demand periods using a target period capacity factor (TPCF) framework as an alternative to natural gas peakers. Also, a new metric called &ldquo, Lifetime Cost of Operation&rdquo, (LCOO) is introduced to provide a metric, focusing on the raw installation and operational costs of PVS technology compared to natural-gas fired peaker plants (simple cycle or conventional combustion turbine) during the target period window. The target period window is the time period during which it is valuable for power plants to provide firm capacity usually during early or late evening peak demand periods in the summer months (from April to September), a framework for which is increasingly being asked for by utilities in recent request for proposals (RFPs). A 50 MWAC PV system with 60 MW/240 MWh battery storage modelled in California can provide &gt, 98% capacity factor over a 7&ndash, 10 p.m. target period with lower LCOO than a conventional combustion turbine natural gas power plant.

Herein, we investigated structural and electrical properties of ultrasonic spray pyrolyzed ZnO thin films (ZnO(USP)) deposited on radio frequency sputtered ZnO nanocolumns (ZnO(Seed)) under various oxygen atmosphere on p-Si substrates. X-ray diffraction data of the samples showed that the samples had a hexagonal structure with a strong (002) preferred orientation. The grain size of ZnO(USP) samples prepared on the seed layer sputtered in 25% and 50% oxygen atmosphere decreased and surface morphology was nanopebbles. ZnO samples prepared on the seed layers exhibited sharp and predominant ultraviolet luminescence at approximately 380 nm. The current–voltage characteristics of the n-ZnO(USP)/n-ZnO(seed)/p-Si heterojunctions were significantly affected by the seed layer preparation conditions. Backward diode behavior was observed for the n-ZnO(USP)/n-ZnO(seed)/p-Si heterojunctions with high donor concentration, in which the seed layers prepared in 100% and 75% argon atmosphere. The carrier concentration value was decreased for the films with the seed layer, obtained at higher oxygen content in the sputtering atmosphere.

Graphene nanosheets (GNS) reinforced Al2O3 nanocomposites were prepared by a rapid sintering route. The microhardness and fracture toughness values of the resulting nanocomposites simultaneously increased due to efficient graphene nanosheet incorporation and chemical interaction with the Al2O3 matrix grains. The properties enhancement is attributed to uniformly dispersed graphene nanosheet in the consolidated structure promoted by high surface roughness and ability of graphene nanosheet to decorate Al2O3 nanoparticles, strong GNS/Al2O3 chemical interaction during colloidal mixing and pullout/crack bridging toughening mechanisms during mechanical testing. The GNS/Al2O3 interaction during different processing stages was thoroughly examined by thermal and structural investigation of the interfacial area. We report formation of an intermediate aluminum oxycarbide phase via a confined carbothermal reduction reaction at the GNS/Al2O3 interface. The graphene nanosheet surface roughness improves GNS/Al2O3 mechanical attachment and chemical compatibility. The Al2O3/GNS interface phase facilitates efficient load transfer, thus delaying failure through impediment of crack propagation. The resulting nanocomposites, therefore, offer superior toughness.

Magnesia tuned alumina ceramic nanocomposites, reinforced with multi-walled carbon nanotubes, were condensed using pressureless and hot-press sintering processes. Densification, microstructure and mechanical properties of the produced nanocomposites were meticulously investigated. Electron microscopy studies revealed the homogenous carbon nanotube dispersion within the alumina matrix and confirmed the retention of carbon nanotubes' distinctive tubular morphology and nanoscale features during the extreme mixing/sintering processes. Pressureless sintered nanocomposites showed meagre mechanical responses due to the poorly-integrated microstructures with a slight improvement upon magnesia addition. Conversely, both the magnesia addition and application of hot-press sintering technique resulted in the nanocomposite formation with near-theoretical densities (~ 99%), well-integrated microstructures and superior mechanical properties. Hot-press sintered nanocomposites incorporating 300 and 600 ppm magnesia exhibited an increase in hardness (10 and 11%), flexural strength (5 and 10%) and fracture toughness (15 and 20%) with respect to similar magnesia-free samples. Compared to monolithic alumina, a decent rise in fracture toughness (37%), flexural strength (22%) and hardness (20%) was observed in the hot-press sintered nanocomposites tuned with merely 600 ppm magnesia. Mechanically superior hot-press sintered magnesia tailored nanocomposites are attractive for several load-bearing structural applications.

Solar cells based on c-Si/porous-Si/CdS/Zn x Cd 1-x O heterojunctions were synthesized by depositing CdS films on c-Si/porous-Si (PS) substrates by electrochemical deposition (ED). PS layers with systematically varied pore diameter (8-45 nm) and were fabricated on p-type c-Si wafers using electrochemical etching. The window layers of Zn x Cd 1-x O with several Zn concentrations(x=0.2; 0.4; 0.5 and 0.6) were also deposited on the CdS buffer layers by ED. The photoelectrical properties of heterojunctions were studied as functions of PS pore size and Zn content in Zn x Cd 1-x O. The optimal pore size and Zn contents were found to be 10 nm and x=0.6, respectively. These yielded a solar cell sample exhibiting an efficiency of 9.9%, the maximum observed in this study. Full Text: PDF References M.A.Green. "Limiting efficiency of bulk and thin-film silicon solar cells in the presence of surface recombination", Progress in Photovoltaic 7, 327 (1999). CrossRef P.Papet, O. Nichiporik, A. Kaminski et al. "Pyramidal texturing of silicon solar cell with TMAH chemical anisotropic etching", Solar Energy Materials and Solar Cells 90, 2319 (2006). CrossRef P. Vitanovet et al. "High-efficiency solar cell using a thin porous silicon layer", Thin Solid Films 297, 299 (1997). CrossRef L. Santinacci et al. "Electrochemical and optical characterizations of anodic porous n-InP(1 0 0) layers", Electrochim. Acta 56, 878 (2010). CrossRef V.Lehmann. "The Physics of Macropore Formation in Low Doped n‐Type Silicon", J. Electrochem. Soc. 140, 2836 (1993). CrossRef Bisi O et al. "Porous silicon: a quantum sponge structure for silicon based optoelectronics", Surface Science Reports 38, 1 (2000). CrossRef A.I. Raid et al. Applied Nanoscience 7, 9 (2016). CrossRef M.A. Naser et al. "Characteristics of Nanostructure Silicon Photodiode using Laser Assisted Etching", Procedia Engineering 53, 393 (2013). CrossRef D.H. Oh et al. J. Ceram. Process. Res. "Effects of a H 2 SO 4 treatment on the optical properties in porous Si layers and electrical properties of diode devices fabricated with a H 2 SO 4 treated porous Si layer", 9, 57 (2008). DirectLink H. Foll et al. "Formation and application of porous silicon", Materials Science and Engineering R 280, 1 (2002). CrossRef P. Granitzer et al. "Porous Silicon—A Versatile Host Material", Materials 3, 943 (2010). CrossRef G. Korotcenkov, Porous Silicon: From Formation to Application (Taylor and Francis Group, CRC Press, Boca Raton, USA, 2016). DirectLink V.Y. Yerokhov. "Porous silicon in solar cell structures: a review of achievements and modern directions of further use", Renewable and Sustainable Energy Rev. 3, 291 (1999). CrossRef A. Ramizy et al. "New optical features to enhance solar cell performance based on porous silicon surfaces", Appl. Surf. Science 257, 6112 (2011). CrossRef F. Ruske et al. "Large area ZnO:Al films with tailored light scattering properties for photovoltaic applications", Thin Solid Films 515, 8695 (2007). CrossRef Y. Alivov et al. "Observation of 430 nm electroluminescence from ZnO/GaN heterojunction light-emitting diodes", Appl. Phys. Lett. 83, 2943 (2003). CrossRef G.V. Lashkarev et al. "Properties of zinc oxide at low and moderate temperatures", Low Temp. Phys. 37, 289 (2011). CrossRef P.M. Devshette et al. "Growth and physical properties of Zn x Cd 1−x O thin films prepared by spray pyrolysis technique", J. of Alloys and Compunds 463, 576 (2008). CrossRef Y. Caglar et al. "Morphological, optical and electrical properties of CdZnO films prepared by sol–gel method", J. Phys. D: Appl. Phys. 42, 065421 (2009). CrossRef A. Abdinov et al. "Photosensitivity of p,n-Si/n-Cd 1−x Zn x S heterojunctions manufactured by a method of electrochemical deposition", Thin Solid Films 480-481, 388 (2005). CrossRef A Abdinov et al. "Investigation of electrodeposited p-Si/Cd 1 − x Zn x S 1 − y Se y heterojunction solar cells", Thin Solid Films 511-512,140 (2006) CrossRef J.B. Orhan et al. "Nano-textured superstrates for thin film silicon solar cells: Status and industrial challenges", Sol. Cells 140, 344 (2015). CrossRef H.Ch. Alan et al. "Light management of tandem solar cells on nanostructured substrates", J. Photon. Energy 7, 027001 (2017) CrossRef

Aramid (Ar), produced from the reaction of aromatic diamines and diacid chloride, was reactively compatibilized with amino-functionalized polystyrene (APS) to explore blend morphology and interfacial cohesion. Two blend systems, Ar/PS and Ar/APS, were investigated over a range of pristine polystyrene (PS) or modified APS ratios. Morphology and thermal and mechanical properties were probed to evaluate the effect of amine units of APS on the compatibility with Ar. π-π stacking interactions in tandem with the random distribution of graft attachment locations and polydispersity of graft length in Ar-g-APS copolymer, aided merger of unreacted chains to drive molecular self-assembly process thus fortifying the nanostructured blends. Considerable augmentation of the blend morphology and thermal stability was achieved by incorporation of reactivity into Ar/APS system. A 20 wt % APS-containing blend was found to demonstrate optimum mechanical reinforcement, complemented by the optimal, thermal, and morphological profiles of the same blend. Future prospects are envisaged.

In this paper, a new and simple method is described that does not use an autoclave to synthesize copper indium gallium diselenide (CuIn0.5Ga0.5Se2) particles from the constituent elements. The process also does not require a post-synthesis selenization step. A solvo-thermal route is followed in which the constituent element powders are dissolved and made to react in a solvent such as ethylenediamine (ED), or triethylenetetramine (TETA). Crystal structure, morphology, composition, and particle size distribution of prepared particles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and dynamic light scattering (DLS), respectively. The band gap energies of the prepared particles were determined using an UV–VIS–NIR spectrophotometer. The results indicate that the solvent temperature and the synthesis time significantly affect the formation of single-phase CuIn0.5Ga0.5Se2 and the crystallinity of the particles. Further, the measured band gap energy for the prepared particles is close to that of the bulk material. For example, the single-phase plate-like CuIn0.5Ga0.5Se2 particles with an average particle size of 413.9 nm which can be successfully synthesized at a temperature of 250 °C in 15 h, have a band gap energy of 1.15 eV.

Multilayer TiO(2)-Ge thin films have been deposited using electron beam evaporation and resistive heating. The thickness of the TiO(2) layers is 20 nm, while the thickness of the Ge layers varies from 2 to 20 nm with a step of 2 nm away from the substrate. These films were characterized by studying their optical, electrical, and structural properties. The films were annealed at various temperatures up to 500 degrees C for 2 h. The films are amorphous up to an annealing temperature of 400 degrees C, although Raman spectra suggest short-range ordering (and adjustments). The films annealed at 450 and 500 degrees C exhibit X-ray reflections of Ge and anatase TiO(2). Illumination in sunlight increases the conductivity of the as-deposited and annealed films. The band gap of the amorphous films changes from 1.27 to 1.41 eV up to 400 degrees C; the major contribution is possibly through direct transition. Two band gap regimes are clearly seen after 450 and 500 degrees C, which have been assigned to an indirect band gap at about 1.2 eV and a direct band gap at about 1.8 eV. Conductivity of the multilayer films has been higher than that of pure Ge film. The conductivity increases with annealing temperature with abrupt increase at about 380 degrees C. The results imply that the TiO(2)-Ge multilayer films may be employed as heterojunctions with tunable band gap energy as related to quantum confinement effects.

The title compound 1,3-bis(p-nitrophenoxy)propane was synthesized by nucleophilic substitution of p-nitrophenol and 1,3-dibromopropane. Single crystal X-ray diffraction analysis reveals that the molecule in the solid state packs in the monoclinic P2/n space group with crystal cell parameters a = 17.465(5) A, b = 4.8433(13) A, c = 17.610(5) A, β = 100.290(6)o, V = 1465.6(7) A3, Dcalc = 1.442 g/cm−3. Two half-molecules are located in the asymmetric unit which are each completed by twofold symmetry making Z = 4, Z′ = 1. The title compound 1, 3-bis (p-nitrophenoxy) propane was prepared from p-nitrophenol and 1, 3-dibromopropane, crystallized from an ethanolic solution, and the structure was obtained by single crystal X-ray diffraction: monoclinic, P2/n, a = 17.465(5) A, b = 4.8433(13) A, c = 17.610(5) A, β = 100.290(6)°, V = 1465.6(7) A3.

Nanoparticles of TiO2 codoped with 0.5, 0.75, and 1 atom-% Nb and Sc each were synthesized by sol–gel technique. After drying, as-synthesized samples were calcined at temperatures ranging from 250–900 °C. Changes in phase transformation of the doped samples with reference to dopant concentration and calcination temperature have been studied. The samples were analyzed by various analytical tools such as XRD, SEM, TEM, XPS, and EDS. The XRD results indicate that the presence of Nb and Sc substitutional ions in the anatase crystal structure inhibits the phase transition and growth of the nanoparticles with an increase in temperature. The XPS results indicate the incorporation of Nb as Nb2O5 and Sc as Sc2O3.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The metallorganic chemical vapor deposition method was successfully used to synthesize pure TiO 2 and Nd 3+ -, Pd 2+ -, Pt 4+ -, and Fe 3+ -doped TiO 2 nanoparticles. Polycrystalline TiO 2 structure was verified with x-ray diffraction, which showed typical characteristic anatase reflections without any separate dopant-related peaks. Transmission electron microscopy observations confirmed the existence of homogeneously distributed 22 ± 3 nm TiO 2 nanoparticles. The particle size remained the same for the doped samples. The doping level of transition metals was kept at ≈1 atomic percent, which was determined by x-ray photoelectron spectra and energy dispersive x-ray spectroscopy. The effects of different types of dopants on the photocatalytic activity were revealed by the degradation of 2-chlorophenols with an UV light source. The photocatalytic efficiency was remarkably enhanced by the introduction of Pd 2+ and Nd 3+ . Nd 3+ -doped TiO 2 showed the largest enhancement. However, Pt 4+ changed the 2-chlorophenol degradation rate only slightly, and Fe 3+ was detrimental to this process. These effects were related to the position of the dopants in the nanoparticles and the difference in their ionic radii with respect to that of Ti 4+ .

Selenization of sputter deposited Cu-In-O films is investigated using two different sputtering targets. Sputter deposition parameters are varied to study the phase formation from Cu2In2O5 and Cu+In2O3 sputtering targets. XRD patterns of sputter deposited thin films from these targets showed different crystal orientation of the In2O3 phases deposited at 300°C and 500°C substrate temperatures. Films prepared by sputtering from Cu2In2O5 target are annealed under H2Se-Ar gas and the films prepared from Cu+In2O3 sputtering are annealed with Se under Ar-H2 gas. XRD results showed that the CuInSe2 phase is formed in all samples and a residual impurity phase In2O3 is identified for some of the films. Additionally, the results suggested that the selenization of Cu-In-O thin film revealed different effects when In2O3 phase is oriented. Additional layers are deposited for solar cell device and the device performances are investigated.

We have determined the electronic and atomic structure of N doped TiO2 using a combination of hard x-ray photoelectron spectroscopy and first-principles density functional theory calculations. Our results reveal that N doping of TiO2 leads to the formation of oxygen vacancies and the combination of both N impurity and oxygen vacancies accounts for the observed visible light catalytic behavior of N doped TiO2.