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To enable heterogeneous integration of InGaAs based transistors with Si complementary metal-oxide-semiconductor (CMOS) devices, metal contacts to n+-InGaAs need to have high thermal stability for CMOS process compatibility and ultra-low contact resistance to achieve good device performance. In this work, n+-InGaAs contacts with ultra-low contact resistivity pc based on refractory metals such as molybdenum (Mo) were realized. Use of refractory metal contacts achieves good thermal stability. An improved process that eliminates oxide between the metal and n+-InGaAs by using an in situ Ar+-plasma treatment prior to metal deposition achieves ultra-low pc. Furthermore, a nano-scale transmission line method (nano-TLM) structure with significantly reduced parasitic leakage was designed and fabricated to improve the pc extraction accuracy. The improved test structure introduces a SiO2 isolation layer between Mo and InGaAs outside the active or mesa region to eliminate a parallel leakage path that is present in other nano-TLM structures reported in the literature. [ABSTRACT FROM AUTHOR]

The structural and optical properties of sputter deposited nitrogen (N) doped CuO (CuO(N)) thin films are systematically investigated. It is found that the incorporation of N into CuO causes an enlargement of optical bandgap and reduction in resistivity of the CuO(N) films. Furthermore, a gradual phase transformation from CuO to Cu2O is observed with the increase in N concentration. The effects of annealing temperature on the structural properties of CuO (N) and its dependence on N concentration are also investigated. It is observed that the phase transformation process from CuO to Cu2O significantly depends on the N concentration and the annealing temperature. Heterojunction solar cells of p-type CuO(N) on n-type silicon (Si) substrate, p-CuO(N)/n-Si, are fabricated to investigate the impact of N doping on its photovoltaic properties. [ABSTRACT FROM AUTHOR]

Developing interfacial connections is one of the breakthrough strategies to improve the photocatalytic activity. Herein, ZnBi 2 O 4 nanoparticles-ZnO nanorods heterojunction was successfully synthesized and used, as a dual-function photocatalyst, for photocatalytic degradation of Bisphenol A and hydrogen production with improved photocatalytic activity under simulated sunlight irradiation. The highest H 2 production (3.44 mmol g−1 h−1) was obtained for ZnO-20 wt% ZnBi 2 O 4 sample, which is around 12.7 times higher than pure ZnO. According to the HRTEM result, the intimate interfacial connections are formed between ZnO and ZnBi 2 O 4 which could act as trapping centers for charge carriers and results in the boosted photocatalytic activity. Further, a high aspect ratio of 1D ZnO nanorods and small size of 0D ZnBi 2 O 4 nanoparticles (~10 nm) increases the number of interfacial contacts and thus the charge carriers' recombination was suppressed more efficiently. Based on the trapping experiments, ESR and Mott-Schottky analysis, ZnBi 2 O 4 –ZnO hybrid photocatalyst followed the S -scheme charge transfer mechanism. • Novel 0D/1D ZnBi 2 O 4 /ZnO p-n heterojunction was successfully prepared. • The prepared hybrid system revealed improved H 2 production and BPA decomposition. • The highest hydrogen evolution (3.44 mmol.g−1.h−1) was achieved on ZnO–20%ZnBi 2 O 4. • S -scheme mechanism was suggested for boosted photocatalytic activity. • The defects formed at the interfacial contacts decreased the recombination rate. [ABSTRACT FROM AUTHOR]

Copper-rich interfacial-layer (Cu-rich IL) is formed during sputter deposition of cupric oxide (CuO) layer on silicon (Si). It has significant impact on the performance of p-CuO/n-Si heterojunction solar cells. In this report, CuO films deposited on Si at different RF-power levels using single and two-step RF-sputtering techniques and p-CuO/n-Si heterojunction solar cells have been investigated. Systematic characterization using XPS, AFM, XRD, Raman, and HR-TEM reveal that twostep RF-sputtering technique offers better crystal quality CuO film with thinner Cu-rich IL layer. Photovoltaic (PV) properties with an open-circuit voltage (Voc) of 421 mV, short circuit current (Jsc) of 4.5 mA/cm2, and a photocurrent of 8.3 mA/cm2 have been achieved for the cells prepared using two-step sputtering method, which are significantly higher than that for the solar cells fabricated using a single-step sputtering. The PV properties were further improved by depositing CuO films at higher working pressure with nitrogen doping. The efficiency of the best device achieved is approximately 1.21%, which is the highest value reported for p-CuO/n-Si heterojunction based solar cells. [ABSTRACT FROM AUTHOR]

• CuO film photocatalyst, photocatalytic degradation. • In-situ thermal treatment, nanocrystal engineered thin CuO film. We design a thin CuO film photocatalyst for visible-light-driven photocatalytic degradation of methylene blue (MB). Nanocrystal engineering of the photocatalyst is performed by sputtering with concurrent in-situ thermal treatment. The impacts of the in-situ thermal treatment temperature and sputtering conditions on the material properties of the thin CuO film photocatalyst are investigated in detail. Systematic characterization using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) indicates that deposition at elevated temperature and higher sputtering power significantly improves the surface structure and crystallinity of thin CuO film, which promotes charge transfer and ultimately results in better performance for MB photocatalytic degradation. The best-performing sample is the one sputtered at an elevated temperature of 300 °C and a sputtering power of 300 W. The photodegradation efficiency and physical durability of the samples were also analyzed after using for 5 cycles. The results indicate that in-situ thermal treatment and nanocrystal engineering of the thin CuO film significantly improve the physical durability. [ABSTRACT FROM AUTHOR]

In this paper, we report a promising sunlight-driven screen-printed TiO 2 porous nanorods (PNR) photoanode decorated with Au plasmonic nanostructures for photoelectrochemical (PEC) light-to-electricity conversion. Fabricated photoanodes were characterized using field emission scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, X-Ray diffraction analysis, X-ray photoelectron spectroscopy, N 2 adsorption-desorption isotherms, UV–vis spectroscopy and electrochemical impedance spectroscopy in detail. The Au-PNR-TiO 2 photoanode demonstrates superior PEC activities both under simulated sunlight and visible light irradiation. Interestingly, the Au-PNR-TiO 2 shows high photocurrent density of 0.71 mA cm −2 at +0.4 V vs. Ag/AgCl, which is 65% higher than the pristine PNR-TiO 2 . It is shown that enhanced surface area, roughness factor, high crystallinity and one-dimensional framework which are offered by screen-printed porous TiO 2 nanorods make a great microenvironment for more accessible reactive sites, light capturing ability, efficient charge generation and smooth transfer of photogenerated charge carriers. Decoration with Au nanoparticles is also shown that play an important role in improving the PEC performance by injecting hot electrons and excellent catalytic effect. [ABSTRACT FROM AUTHOR]

A thin cupric oxide film (CuO), straddled with graphene nanoparticles, is proposed as a promising absorber layer for solar cell application. The influence of the graphene nano-particles on the optical, electrical, and photovoltaic properties of the CuO thin film is investigated in detail. Graphene nano-particles incorporated CuO (G-CuO) film, grown via sol-gel deposition, shows a reduction in the optical transmittance and reflectance, and an enhancement in its electrical conductivity. Photovoltaic properties, investigated through a p-(G-CuO)/n-Si heterojunction cell, shows a significant increase in short circuit current from 0.12mA/cm² to 0.82mA/cm². The fill factor was also found to increase to 40% from 20%. The significant improvement in efficiency of the G-CuO solar cell is attributed to the synergetic effect provided by graphene in enhancing the absorption of visible light and increasing its electrical conductivity, while concurrently suppressing charge recombination in the bulk semiconductor. [ABSTRACT FROM AUTHOR]

The potential of titanium (Ti) incorporation into cupric oxide (CuO) is demonstrated. The optical, electrical, microstructural, material quality, chemical composition, surface morphology, and photovoltaic properties of Ti doped CuO, CuO(Ti) have been systematically investigated. It is shown that Ti doped CuO reduces sheet resistance and improved the charge transport properties. Furthermore, by tuning the Ti concentration, the conductivity of CuO(Ti) can be improved, while retaining the optical properties and crystallinity of the samples. Heterojunction solar cells of p -type Ti doped CuO on n -type silicon (Si) substrate, p -CuO(Ti)/ n -Si, prepared by using conventional sputter deposition at room temperature followed by rapid thermal annealing at 300 °C to investigate the impact of Ti doped CuO on the performance of photovoltaic properties. The short circuit current and efficiency of p -CuO(Ti)/ n -Si heterojunction have been significantly improved compared to the cells without Ti doped CuO. [ABSTRACT FROM AUTHOR]

We present an analytic approach to model the velocity enhancement in high field devices with sub-100-nm multiplication regions. In doing so, we consider the energy loss caused by collision between carriers and optical phonons. By inclusion of such effects, we modify carriers' path distance probability density functions (PDFs) for both time and space domain. Using our modified PDFs, we extract a more accurate set of impact ionization coefficients and ionization threshold energies for ultra-thin GaAs-, AlGaAs- and InAlAs-APDs with multiplication regions as narrow as 25 nm. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we have presented electric field dependence of the electron and hole impact ionization coefficients and threshold energies in submicron Si diodes with intrinsic region thicknesses down to 31 nm. To do so, we have used a nonlocal analysis, in order to take the effects of arbitrary distribution of ionization events in both space and time domains and the effects of enhancement in the average speed of those carriers which ionize early in their trajectories as well as nonuniform electric fields in the multiplication region and its surrounding ambient, carrier’s dead space history and its spatial ionization rate, into consideration all in one comprehensive analytic model. [Copyright &y& Elsevier]

In this paper, we have introduced an efficient analytic approach to study the effects of optical phonon scattering loss on the characteristics of avalanche photodiode (APDs) with multiplication regions as narrow as 25 nm. To do so, we have considered the energy loss caused by collision between carriers and optical phonons. We have also considered the effects of the carrier's dead space and its previous ionization history to develop a new compact model for predicting multiplication gains as well as breakdown conditions in APDs valid for a vast range of temperature. These predicted values can be used to extract carriers' impact ionization coefficients and ionization threshold energies. As an example, we have used our model to predict and extract the aforementioned characteristics and parameters for Al0.6Ga0.4As-APDs operating at temperatures over the range of 13 K ⩽ T ⩽ 290 K. Comparison of these results with experimental data available in literature has demonstrated the capability of the new developed model as a powerful tool for simulating APDs' behavior and interpreting their experimentally measured characteristics. [ABSTRACT FROM AUTHOR]

• Oxygen vacancy and excess generation by sputtering. • Effect of the oxygen vacancy and excess on the photocatalytic activity of CuO samples. • Comparison the duarability of the oxygen vacancy and excess. CuO thin films with oxygen defects (oxygen vacancy and oxygen excess) were prepared by sputter deposition from stochiometric CuO target. Presence of Oxygen defects was confirmed by X-ray photoelectron spectroscopy. Effect of oxygen vacancy and excess on the photocatalytic activity (Triclosan (TS) degradation) of CuO thin films under sunlight irradiation was investigated. Generation of oxygen vacancy (lower than optimum concentration) and excess considerably improved the thin film photocatalytic activity. In original work, the photocatalytic activity of the samples with oxygen vacancy was compared to the ones with oxygen excess. Moreover, the durability of the samples (oxygen vacancy and excess) after several cycles was investigated. The samples with oxygen excess showed better photocatalytic activity; though, the durability of samples with oxygen vacancy was significantly superior to the ones with oxygen excess after 5 cycles. [ABSTRACT FROM AUTHOR]

• A comprehensive review over the synthesis of anatase TiO 2 facets. • Photocatalytic applications of different types of anatase TiO 2 facets. • The effect of the tailored facets of anatase on the charge carrier's separation. • The future outlook for the facets engineering of the anatase crystals. Anatase titanium dioxide, as one of the most well-known functional materials, is widely utilized in various fields of the environment and energy. In recent decades, much attention has been attracted to the surface engineering of the anatase crystal at a microscopic level for a better understanding of the relationship between surface and photocatalytic activity. In this review, a brief description is presented for the synthesis of the low-index facets ({0 0 1}, {1 0 0}, {1 0 1}, {1 1 0} and {1 1 1}) and high-index facets. Besides, the comparison between the photocatalytic activity of the faceted anatase and common types of TiO 2 (mostly P25) is performed in this review. Meanwhile, a comprehensive study for the comparison between photocatalytic performance (organic pollutants photodegradation and water splitting) of the various types of the low-index facets and high-index facets is performed. The location of the band edge and band gap value in semiconductors during photocatalytic reaction play an important role in energy requirements for electron transfer and the light absorption respectively; so, band gap and band edge location in various types of anatase TiO 2 facets are investigated. The recombination rate of the photogenerated electron–hole pairs is commonly described as one of the main limiting factors for the photocatalytic activity of the TiO 2. In this review, the effect of the tailored facets of anatase crystal on the charge carrier's separation as a promising strategy is completely described. Finally, the novel ideas for future studies on the facets engineering of the anatase crystals are also suggested. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have emerged recently as promising candidates for next generation photovoltaics and have reached power conversion efficiencies of 25.2%. Among the various methods to advance solar cell technologies, the implementation of nanoparticles with plasmonic effects is an alternative way for photon and charge carrier management. Surface plasmons at the interfaces or surfaces of sophisticated metal nanostructures are able to interact with electromagnetic radiation. The properties of surface plasmons can be tuned specifically by controlling the shape, size, and dielectric environment of the metal nanostructures. Thus, incorporating metallic nanostructures in solar cells is reported as a possible strategy to explore the enhancement of energy conversion efficiency mainly in semi‐transparent solar cells. One particularly interesting option is PSCs with plasmonic structures enable thinner photovoltaic absorber layers without compromising their thickness while maintaining a high light harvest. In this Review, the effects of plasmonic nanostructures in electron transport material, perovskite absorbers, the hole transport material, as well as enhancement of effective refractive index of the medium and the resulting solar cell performance are presented. Aside from providing general considerations and a review of plasmonic nanostructures, the current efforts to introduce these plasmonic structures into semi‐transparent solar cells are outlined. [ABSTRACT FROM AUTHOR]

Ga and Sn surface-segregated GeSn (Seg. p+-GeSn) layer with an average active Ga doping concentration of $3.4 \times 10^{20}$ cm $^{-3}$ and surface Sn composition of ~7% was grown on the Ge (100) substrate by molecular beam epitaxy. An ultralow specific contact resistivity $\rho _{\textsf{c}}$ down to $4.4 \times 10^{-\textsf {10}} \,\,\Omega \cdot \text {cm}^{\textsf {2}}$ is achieved for the Ti contact on Seg. p+-GeSn film. Average $\rho _{\textsf{c}}$ , extracted from 14 sets of nano-scale transmission line method test structures and a collection of more than 90 devices, is $6.5 \times 10^{-\textsf {10}} \,\,\Omega \cdot \textsf {cm}^{\textsf {2}}$. This is the lowest $\rho _{\textsf {c}}$ for any nonlaser-annealed contacts. In addition, the benefits of Ga and Sn surface segregation on $\rho _{\textsf {c}}$ reduction were investigated. Increasing the surface Sn composition from 5% to 8% lowers $\rho _{\textsf {c}}$ from $1.4\times 10^{-\textsf {9}}$ to $1.1\times 10^{-\textsf {9}} \,\,\Omega \cdot \textsf {cm}^{\textsf {2}}$ and the Ga surface segregation further reduces $\rho _{c}$ down to $6.5\times 10^{-\textsf {10}} \,\,\Omega \cdot \textsf {cm}^{\textsf {2}}$. [ABSTRACT FROM AUTHOR]

The current state of thin film heterojunction solar cells based on cuprous oxide (Cu2O), cupric oxide (CuO) and copper (III) oxide (Cu4O3) is reviewed. These p-type semiconducting oxides prepared by Cu oxidation, sputtering or electrochemical deposition are non-toxic, sustainable photovoltaic materials with application potential for solar electricity. However, defects at the copper oxide heterojunction and film quality are still major constraining factors for achieving high power conversion efficiency, η. Amongst the Cu2O heterojunction devices, a maximum η of 6.1% has been obtained by using pulsed laser deposition (PLD) of AlxGa1-xO onto thermal Cu2O doped with Na. The performance of CuO/n-Si heterojunction solar cells formed by magnetron sputtering of CuO is presently limited by both native oxide and Cu rich copper oxide layers at the heterointerface. These interfacial layers can be reduced by using a two-step sputtering process. A high η of 2.88% for CuO heterojunction solar cells has been achieved by incorporation of mixed phase CuO/Cu2O nanopowder. CuO/Cu2O heterojunction solar cells fabricated by electrodeposition and electrochemical doping has a maximum efficiency of 0.64% after surface defect passivation and annealing. Finally, early stage study of Cu4O3/GaN deposited on sapphire substrate has shown a photovoltaic effect and an η of ~10-2%. [ABSTRACT FROM AUTHOR]

Structural properties and solar cells performance of sputter grown sub-micrometer thick (~600 nm) Cu 2 ZnSnS 4 (CZTS) films are investigated for low cost and large scale photovoltaic deployment. The CZTS films are deposited using single quaternary stoichiometric target at room temperature. X-ray diffraction, micro-Raman spectroscopy, and scanning electron microscopy measurements were carried out to investigate the structural property and secondary phase formation. The intense phonon peak at 334 cm −1 in the visible Raman spectra confirms the deposition of single phase CZTS films. CZTS-based thin film solar cells show excellent performance with open circuit voltage ~600 mV and over all cell efficiency of ~3.07%, exhibiting commercial potential toward large scale fabrication of photovoltaic devices. [ABSTRACT FROM AUTHOR]

Growth of alpha phase aluminum alloyed iron silicide (α-phase FeSi(Al)) ternary alloy on silicon (Si) substrate at a temperature of 600 °C has been reported. The α-phase FeSi(Al) thin films are grown on Si substrate by using conventional sputter deposition and rapid thermal annealing (RTA) treatment. The transition temperature of α-phase FeSi 2 reduces to 600 °C through incorporating aluminum into the silicide films. Thickness of amorphous silicide layer and aluminum composition are very critical to grow highly texture α-FeSi(Al) layer at a lower temperature. The α-FeSi(Al) film shows a preferential orientation (001) after annealed at temperature of 600 °C through the formation of thin film epitaxial silicon at the interface. The α-FeSi(Al) films tends to show a polycrystalline nature with the increase on annealing temperature to 700 °C. The α-FeSi(Al) ternary alloy has high work function of ∼5.3 eV. The low temperature grown α-phase FeSi(Al) can be applied for renewable energy and electronic applications as an electrode. [ABSTRACT FROM AUTHOR]

• V-doped Ni-Mo-P nanostructure was fabricated using electrochemical deposition. • Fabricated electrode exhibited outstanding electrocatalytic HER and OER activity. • Synergistic effect and high surface area was main reason for excellent performance. • Deposited electrode represented outstanding electrocatalytic durability. The emergence and fabrication of cost-effective and active electrodes in the overall water splitting process are one of the most critical challenges for hydrogen production. Here, firstly Ni-P electrodes were generated at different scan rates using the electrochemical deposition method, and then molybdenum was doped in Ni-P structure using the same method and vanadium using hydrothermal deposition method, and V-doped Ni-Mo-P electrode was generated. It was revealed that the synthesized electrode displays outstanding electrochemical properties for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For reaching a current density of 10 mA cm −2, the optimum sample needed only 65 mV in the HER process and only 261 mV of overpotential in the OER process. In addition, the electrocatalytic stability investigation disclosed that this electrode had excellent durability at the 100 mA cm −2 in HER and OER process after 10 h of electrolysis in which only less than 2 % increase in overpotential was observed, which indicates excellent electrocatalytic stability. Such outstanding electrocatalytic properties were mainly because of increasing the active surface area and the synergistic effect due to doping of molybdenum and vanadium in the electrode structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel visible driven WO 3 -CeO 2 heterojunction was successfully synthesized. • The prepared photocatalyst was applied for degradation of Sulfamerazine from an aqueous solution. • Incorporation of CeO 2 on WO 3 significantly enhanced the photodegradation percentage. • S-scheme mechanism was suggested for the boosted photocatalytic activity. • Photodegradation pathways of Sulfamerazine antibiotic were investigated. In this work, hierarchical WO 3 -CeO 2 hollow sphere heterojunctions were fabricated via a two-step hydrothermal method and applied for degradation of sulfamerazine antibiotic under visible light irradiation. The incorporation of CeO 2 into the WO 3 microspheres was confirmed by XRD, BET, HRTEM, and XPS analysis. The results revealed that the photocatalytic activity of WO 3 -CeO 2 heterojunction was greatly enhanced compared to pure CeO 2 and WO 3 samples, and the highest degradation percentage of sulfamerazine was achieved on the WO 3 -CeO 2 heterojunction with 30 mol. % CeO 2 content. This could be ascribed to the efficient separation of charge carriers which was facilitated by oxygen vacancies formed at the interfaces of two coupled semiconductors. EIS analysis verified that the charge transfer resistance of WO 3 -30CeO 2 heterojunction was decreased, which is due to the heterojunction effect. Moreover, based on the Mott-Schottky calculations, radical trapping experiments and ESR analysis, hydroxide radicals were identified as the main active species, and an S-scheme charge transfer mechanism was suggested to explain the enhanced photocatalytic activity. The possible degradation pathway of sulfamerazine was suggested through the detection of degradation intermediates by mass spectroscopy. [ABSTRACT FROM AUTHOR]

In this report, the photocatalytic activity of P25 has been explored and the influence of thermal treatment under various atmospheres (air, vacuum and hydrogen) were discussed. The samples' characteristics were disclosed by means of various instruments including X-ray diffraction (XRD), Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS) and UV–vis. This study also accentuates various states of the oxygen vacancy density formed inside the samples as well as the colour turning observed in treated P25 under various atmospheres. Produced coloured TiO2 samples were then exploited for their photocatalytic capability concerning photodegradation of methylene blue (MB) using air mass (AM) 1.5 G solar light irradiation. Our findings revealed that exceptional photocatalytic activity of P25 is related to the thermal treatment. Neither oxygen vacancy formation nor photocatalytic activity enhancement was observed in the air-treated sample. H2-treated samples have shown better photoactivity which even could be further improved by optimizing treatment conditions to achieve the advantages of the positive role of oxygen vacancy (O-vacancy at higher concentration than optimum acts as electron trapping sites). The chemical structure and stability of the samples were also studied. There was no sign of deteriorating of O2-vacancies inside the samples after 6 months. High stability of thermal treated samples in terms of both long and short-term time intervals is another significant feature of the produced photocatalyst. [ABSTRACT FROM AUTHOR]

Germanium–tin (GeSn) p-channel fin field-effect transistor (p-FinFET) was realized on a novel GeSn-on-insulator (GeSnOI) substrate. The high-quality GeSnOI substrate was formed using direct wafer bonding technique and was layer-transferred from a 300-mm GeSn/Ge/Si donor wafer. Material quality was examined using atomic force microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, and high-resolution X-ray diffraction. The fabricated GeSn p-FinFETs exhibit a small subthreshold swing (${S}$) of 79 mV/decade at ${V}_{\text {DS}}$ of −0.05 V (by a device with ${L}_{\text {CH}}$ of 200 nm and ${W}_{\text {Fin}}$ of 30 nm), good control of short channel effects, and high intrinsic transconductance (${G}_{m,\text {int}} = 702\,\,\mu \text {S}/\mu \text{m}$ at ${V}_{\text {DS}}$ of −0.5 V for ${L}_{\text {CH}}$ of 80 nm). Low-temperature mobility analysis was performed on the GeSn p-FinFETs. High effective hole mobility ($\mu _{\text {eff}}$) (210 cm2/ $\text {V}\cdot \text {s}$ at 290 K and 398 cm2/ $\text {V}\cdot \text {s}$ at 5 K) is achieved. The GeSn p-FinFETs presented in this paper exhibit the highest ${G}_{m,\text {int}}/{S}_{\text {sat}}$ at ${V}_{\text {DS}}$ of −0.5 V for all the reported GeSn p-FETs to date. [ABSTRACT FROM AUTHOR]

This review highlights the development of energy saving transparent heat regulating (THR) materials and coating for energy saving window applications. Current state-of-the-art technologies including transparent heat reflecting mirror (THM), thermo-chromic (TC), transparent solar cells (TSC), and luminescent based materials have been discussed. The coating performance primarily depends on the selection of materials, surface and structural morphology, dielectric passivation growth process and architecture of the multi-layered structure. The micro-structural properties of thin metal/metal oxide layer, and its impact on the heat reflecting coating have been studied extensively. Growth of high quality continuous thin film with fewer defects is an essential part of the infrared reflecting and/or heat regulating coatings. Henceforth, in this review, detailed analysis of growth of continuous and thin metal layer influence of the seed layer (germanium and nickel) and doping on the growth mechanism of thin metal have been discussed. Surface morphology and electronic properties of metal layer/multi-layered coatings have been studied in detail for THR applications. A wide range of metal oxides and their physical properties have been considered for use as passivation layer in the THR coating structure. Among several THR structures, the architecture comprising of dielectric-metal-dielectric (DMD) stack is known to exhibit the best heat reflecting performances. While the metal component typically comprises of silver (Ag), copper (Cu), and nitride based materials, dielectrics are made from metal oxides such as BaSnO 3 , TiO 2 , SnO 2 , ZnO, HfO 2 , Cu 2 O, and ZrO 2 . Selection of passivation layer and tuning of micro-structural properties are very crucial to enhance the visible transmittance without sacrificing infrared reflectance. Optical properties of the dielectric layer can be controlled with growth mechanism and varying content of impurity dopant. Metal doped dielectrics play a key role to enhance the visible light transmission while maintaining infra-red reflection. Through in-situ materials engineering, crystal quality of the dielectric improves which has significant role on the THR performance. Furthermore, impact of rapid thermal annealing (RTA) technique to improve crystal quality of metal oxides without oxidizing the thin metal layer is also emphasized. In the subsequent sections, synthesis of thin films by using sputtering methods, thermal evaporation and e-beam evaporation methods using inexpensive materials for large scale deployment of coating have been discussed. Neutral colored Cu-based THR smart windows is developed through tuning the structural property of TiO 2 . The simulated Cu-based THR window shows ≥10 °C temperature reduction when compared to conventional glass based windows. Thermal stability of copper and silver based multilayer enhanced through ultra-thin metal and dielectric interface engineering. Transparent conducting oxides (TCOs) are also an essential candidate for the wide band gap semiconductor based THR application. Recent progress in TCOs material has been briefly discussed in one of the section of the review. Hetero-epitaxy of metal oxides (ITO/ZnO) shows promising characteristics as heat insulating materials. Impact of growth process and surface morphology of the TCO have been studied to evaluate the performance of the TCO as heat insulating materials. In addition, advanced hybrid composite based heat reflector coatings for energy efficient building applications is also highlighted in the later section of the review. The industrial utilization and efficacy of heat reflector metal oxides, when incorporated into polymeric/pigments/fibers and heat reflecting durable paints as advanced hybrid composites coatings has been discussed. The progression of solution based metal nanowire (MNW) and optical properties for the heat regulating applications have been included. Dielectric/metal-NW/dielectric multilayer can be a potential candidate for the development of low cost THR film. The solution based THR methods has potential to be mass customized in economic ways and can be viable at industrial scale. Thermo-chromic materials are also considered as prospective candidate for the transparent coating applications. Recent development of VO 2 bilayer, trilayer, micro-pattern and nano-plate films have been discusses to enhance the luminous transmittance and solar modulation ability. Transparent solar cells, based on the infra-red absorption through up-conversion nanoparticles are viable candidates for the development of environmental friendly heat regulating systems. Recent advancement of inorganic, polymer, perovskite, and luminescent based transparent solar cell (TSCs) with heat reflecting mirror have been evaluated for smart windows applications. For the deployment of large scale THR film, low cost materials, roll-to-roll (R2R) sputter and atmospheric pressure chemical vapour deposition (APCVD) have been assessed for the industrial applicability. The progression of THR materials with thermo-chromics, self-cleaning and TSCs materials can enhance the overall performance of the smart/transparent coatings for thermal management and heat regulating functionalities. [ABSTRACT FROM AUTHOR]

We investigate the thermal stability of germanium-tin (Ge1-xSnx) fins under rapid thermal annealing in N2 ambient. The Ge1-xSnx fins were formed on a GeSn-on-insulator substrate and were found to be less thermally stable than blanket Ge1-xSnx films. The morphology change and material quality of the annealed Ge1-xSnx fin are investigated using scanning electron microscopy, Raman spectroscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and electron energy loss spectroscopy. Obvious degradation of crystalline quality of the Ge0.96Sn0.04 fin was observed, and a thin Ge layer was formed on the SiO2 surface near the Ge0.96Sn0.04 fin region after 500 °C anneal. A model was proposed to explain the morphology change of the Ge0.96Sn0.04 fin. [ABSTRACT FROM AUTHOR]

Thin film photovoltaic Cu 2 ZnSnS 4 (copper zinc tin sulfide or CZTS) is one of the most promising sustainable solar cell absorber material. The CZTS absorber layer containing earth-abundant materials such as copper, zinc, tin and sulfur can be an alternative to existing materials for thin film solar cells. Recently, there has been an increased interest to step-up the efficiency and step-down the manufacturing cost of CZTS-based solar cells. This review critically addresses the advantages and challenges associated with sputter-deposited CZTS solar cells, since sputtering is an industry compatible and relatively low-cost vacuum deposition technique. Various approaches to fabricate CZTS thin films by sputtering are discussed. In addition, the single target quaternary CZTS sputtering technique has been discussed in detail. Current state-of-the art device architectures and methods to improve the quality of interfaces are discussed. This review is intended to highlight current trends and challenges in the field to realize the opportunity of CZTS thin film solar cells for large scale application. [ABSTRACT FROM AUTHOR]

Ag doped Sn 3 O 4 Nanostructure and immobilized on hyperbranched polypyrrole is investigated in this project. The product was synthesized by the hydrothermal synthesis method. The surface and structural characteristics of the product was studied by different instrumental analysis. The fabricated nanocomposites was utilized as a nano photocatalyst in the removal of methylene blue dye. The crystallography results depicts the triclinic phase of Sn 3 O 4 with the crystallite size 36.3 nm. The band gap of the Ag-Sn 3 O 4 /hyperbranched polypyrrole was found 1.50 eV from kubelka-munk measurements. The specific surface area was increased in the presence of the hyperbranched polypyrrole as compared to Ag-Sn 3 O 4 samples. The photo-catalytic activity of composites was found 100.0% degradation of CR in 30 min under visible light irradiation. The catalytic kinetic was followed from the first kinetic model. Moreover, the Ag/Sn 3 O 4 /hyperbranched polypyrrole was applied as a bactericidal agent against Streptococcus pneumoniae , and Pseudomonas aeruginosa bacteria. Determination of Streptococcus pyogenes as a pathogenic bacteria was investigated by using aptamer/Ag/Sn 3 O 4 /hyperbranched polypyrrole in peroxidase activity. The detection limit of S. pyogenes was 71.0 CFU/mL by using the nano-aptamer. • Ag/Sn 3 O 4 /HPPy prepared by chemical method. • The Ag/Sn 3 O 4 /HPPy was studied for degradation of CR dye under visible light. • The Ag/Sn 3 O 4 /HPPy showed excellent anti-bacterial activity. • The bacterial detection was conducted by using the aptamer-Ag/Sn 3 O 4 /HPPy. [ABSTRACT FROM AUTHOR]

• C-doped CuO/g-C 3 N 4 was prepared via facile, one-pot method using low-cost precursors. • Photocathodes were directly deposited on FTO substrate under microwave irradiation. • The amount of urea determined the microstructure of CuO and its optical properties. • Superiority of our synthesis method over many other solution-based ones is explored. • Mechanisms for heterojunction formation and PEC performance improvement are proposed. Cupric oxide (CuO) is a semiconductor of choice for photocathode in photoelectrochemical (PEC) applications due to its great sunlight absorption capability. However, photocorrosion is the main drawback of CuO. Herein, CuO/graphitic carbon nitride (g-C 3 N 4) with a unique microstructure, enhanced PEC performance, and considerable photostability is synthesized under microwave irradiation. A facile, one-pot method is utilized to directly deposit the nanocomposite onto fluorine-doped tin oxide from a solution containing copper precursor and urea. Possible mechanism of CuO/g-C 3 N 4 formation through this novel method is investigated. It is elucidated that controlled amounts of urea critically determine the morphological evolution of CuO, while its excess quantities convert to g-C 3 N 4 in the presence of CuO as the catalyst. Through an appropriate heat treatment, carbon is doped into CuO lattice. The obtained C-doped CuO/g-C 3 N 4 demonstrates 227% enhancement over CuO in photocurrent density and ~80% photocurrent retention. The enhanced photoelectrocatalytic activity is mainly attributed to unique morphology of CuO, effective separation of charge carriers, and formation of heterojunction. These characteristics manifest the superiority of this approach over many other chemical-based methods. The nanocomposite synergistically integrates the advantages of both the constituents, offering a low-cost, efficient photocathode for PEC water splitting, photocatalytic hydrogen evolution, and degradation of pollutants. [ABSTRACT FROM AUTHOR]

A high recombination rate and low charge collection are the main limiting factors of copper oxides (cupric and cuprous oxide) for the photocatalytic degradation of organic pollutants. In this paper, a high performance copper oxide photocatalyst was developed by integrating cupric oxide (CuO) and cuprous oxide (Cu2O) thin films, which showed superior performance for the photocatalytic degradation of methylene blue (MB) compared to the control CuO and Cu2O photocatalyst. Our results show that a heterojunction photocatalyst of CuO–Cu2O thin films could significantly increase the charge collection, reduce the recombination rate, and improve the photocatalytic activity. [ABSTRACT FROM AUTHOR]

Strain relaxation of biaxially strained Ge1-xSnx layer when it is patterned into Ge1-xSnx fin structures is studied. Ge1-xSnx-on-insulator (GeSnOI) substrate was realized using a direct wafer bonding (DWB) technique and Ge1-xSnx fin structures were formed by electron beam lithography (EBL) patterning and dry etching. The strain in the Ge1-xSnx fins having fin widths (WFin) ranging from 1 μm down to 80 nm was characterized using micro-Raman spectroscopy. Raman measurements show that the strain relaxation increases with decreasing WFin. Finite element (FE) simulation shows that the strain component in the transverse direction relaxes with decreasing WFin, while the strain component along the fin direction remains unchanged. For various Ge1-xSnx fin widths, transverse strain relaxation was further extracted using micro-Raman spectroscopy, which is consistent with the simulation results. [ABSTRACT FROM AUTHOR]