Search

Zinc selenide (ZnSe) thin films were deposited on non-conducting glass substrates at different selenium concentrations using a photo-assisted chemical bath deposition method. The films were deposited for 2.0 h at 80 °C and annealed for 2.0 h at 250 °C. X-ray diffraction (XRD) revealed a hexagonal structure with preferential orientation along the (002) plane, and the crystallite sizes were about 9–11 nm. Raman scattering showed longitudinal optical phonon modes due to the ZnSe, and the effect of the selenium concentration was noticed on the peak intensities of the XRD and Raman scattering studies. Optical analysis showed higher absorbance in the visible region than near the infrared spectrum, making the thin films good materials for selective absorber surfaces. The estimated bandgap ranged between 2.37 and 2.70 eV. X-ray spectroscopy confirmed the presence of the desired elements and revealed that the ratio of selenium to zinc declined after the sample was prepared with 0.6 M selenium ions. Photoluminescence studies revealed three emission peaks, which were due to defect state levels in the ZnSe. By varying the selenium concentration, the ZnSe was tuned to a reddish color emission, as confirmed by Commission Internationale de L'Eclairage (CIE) color chromaticity analysis. The selective absorption, wide bandgap, and emission properties suggest that the material is promising for light-emitting device applications. [ABSTRACT FROM AUTHOR]

The work is devoted to the study of the second-harmonic generation (SHG) process as a result of random quasi-phase-matching of thulium laser radiation in ZnSe polycrystals. A linear dependence of the SHG efficiency on the nonlinear medium length has been observed in the experiment. The efficiencies of SHG in ZnSe polycrystals with average grain sizes from 35 μ m to 380 μ m were compared. The obtained results are in good agreement with the theory in the case of a Gaussian grain size distribution. [ABSTRACT FROM AUTHOR]

This treatise showcases the design as well as modeling about a photodetector (PD) based on AgInSe2 (AISe), a direct bandgap chalcopyrite with a bandgap of 1.19 eV. The PD exhibits outstanding optical and electronic characteristics, showcasing remarkable performance. The PD has been systematically investigated by varying the width, carrier density, and defect densities of specific layers, as well as the interface defect density of specific interfaces. Various layers are optimized to enhance the overall performance of the PD and the impact of different device resistances is analyzed. The photocurrent (JSC) and voltage (VOC) of the heterostructure photodetector are determined to be 38.60 mA/cm2 and 1.0 V, in turn. The maximum responsivity (R) and detectivity (D*) are identified as 0.70 A/W and 4.60 × 1016 Jones, respectively at a wavelength of 940 nm. The spectral response exhibits significantly higher values in the range of 800–1000 nm, indicating the device's capability to detect near‐infrared (NIR) light. This research provides valuable insights for the manufacturing of AISe material‐based photodetectors with enhanced performance. [ABSTRACT FROM AUTHOR]

ZnSe thin films were deposited on nonconducting glass substrates using different Zn2+ ion concentrations. The films were deposited at 80∘C for 2.0h via photo-assisted chemical bath technique and annealed for 2.0h at 250∘C. X-ray diffraction revealed a hexagonal structure with preferred orientation along the (002) plane and the average crystallite size decreased from 10.5nm to 6.8nm with increased Zn2+ ions. Raman spectra were used to confirm ZnSe phonon modes whose intensity increased with Zn2+ ion concentrations although with fluctuation. Optical analysis showed higher absorbance and low transmittance in the visible region than near infrared making the thin films good materials for selective absorber surfaces. The band gap increased from 2.52eV to 2.78eV as the Zn2+ ion concentration varied from 0.05% to 0.25%. The presence of the desired elements was confirmed by the EDS. Photoluminescence studies revealed three emission peaks which were all ascribed to defect state levels in ZnSe and all the samples emitted in reddish color according to CIE color chromaticity analysis. The selective absorption, wide band gap and broad emission properties suggest that the material is promising for optoelectronic applications. [ABSTRACT FROM AUTHOR]

This research is devoted to the fabrication of zinc selenide nanostructures using the pulsed laser deposition (PLD) technique in a vacuum under a pressure of 2. 5 × 1 0 − 2 mbar. The structure and structural properties were studied, as it was observed that it had polycrystalline structures and showed peaks for zinc and selenium and peaks belonging to the compound zinc selenide. As for the morphological characteristics of the nanostructures, the structures showed the nature of the surface and the roughness to identify its surface properties. Photocatalysis was carried out using several techniques (visible light, ultraviolet radiation and cold plasma), where a plasma jet system produced under normal atmospheric pressure was used in the treatment, with an exposure time of 4 min and an argon gas flow rate of 3 l/min. The hydrophilic properties were studied to apply these compositions in the self-cleaning process and photocatalytic activity. The results show that the ZnSe nanostructures have high wettability under UV light which has been shown to have excellent catalysis in the UV region, making its application as a self-cleaning material an attractive option. [ABSTRACT FROM AUTHOR]

The physical properties of pure and defected ZnSe wurtzite systems were theoretically investigated. From the first-principle study, the wide band gap is 2.7 eV and ZnSe is a non-magnetic direct band-gap semiconductor. The ferromagnetic and antiferromagnetic states are also studied for Fe-doped ZnSe systems. Investigations show that adding iron and the presence of a single Zn vacancy defect leads to the magnetisation of ZnSe. The total energy calculations show that a ferromagnetic state is favourable when Zn is replaced with Fe. The ferromagnetic alignment in the Fe-doped ZnSe wurtzite compound allows it to be in high-spin and half-metallic states. In cases of Zn interstitial and Se vacancy defect in the ZnSe system does not lead to magnetisation. Defect formation energies and Curie temperature of Fe-doped ZnSe systems are estimated from ab-initio calculations. [ABSTRACT FROM AUTHOR]

The potential use of large-size ZnSe quantum dots as blue emitters for display applications has greatly inspired the colloidal synthesis. Herein, we report the negative effects of side reactions of large-size ZnSe quantum dots. The side reactions between oleic acid and oleylamine generated amidation products and H2O, which led to the hydrolysis of Zn(OA)2 to Zn(OH)2 and the subsequent formation of zinc oxide (ZnO) and zinc bis[diphenylphosphinate] (Zn(DPPA)2) precipitates. These side reactions resulted in the formation of a defective surface including a Se-rich surface and oxygen-related defects. Such negative effects can be overcome by adopting an etching strategy using potassium fluoride and myristic acid in combination. By overcoating a ZnS shell, blue emissive ZnSe/ZnS quantum dots with a maximum photoluminescence quantum yield of up to 91% were obtained. We further fabricated ZnSe quantum dots-based blue light-emitting diodes with an emission peak at 456 nm. The device showed a turn-on voltage of 2.7 V with a maximum external quantum efficiency of 4.2% and a maximum luminance of 1223 cd·m−2. [ABSTRACT FROM AUTHOR]

Magic sized ZnSe nanoclusters have applications in a wide range of areas, such as bioimaging, bio-detection techniques, LEDs and solar cells etc. Despite extensive studies done on ZnSe quantum dots (QDs), the technological potential of photonic behaviour of their lower size range clusters is still largely unexplored. We herein present rapid mustered oil mediated synthesis of magic sized ZnSe with their identification as single-family entities by trapping a fixed position doublet in their absorption spectra. Consistent absorption peaks at 304/305 and 318/19 ​nm irrespective of methods employed are presented. The PL spectra show broad emissions between 350 and 550 ​nm dominating blue region of energy offering scope of further tunability. The mustard oil mediated synthesis was performed using thermal, microwave and ultrasound energy. Despite their size domain of about 2 ​nm, their broad XRD pattern have signature of crystalline nature. Mass spectrometry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are in good support of ZnSe magic size clusters. Typically, blue region CIE coordinates are estimated from PL emission spectra.

Herein, we report the facile synthesis of ZnSe/HPMC (Hydroxypropyl Methyl Cellulose) nanocomposites by in-situ method. The biodegradable HPMC polymer acts as capping molecule as well as polymer matrix. The optical and structural properties of ZnSe/HPMC nanocomposites were studied by optical absorption, photoluminescence (PL) spectroscopy, FTIR, XRD and TEM measurements. Size of the ZnSe nanoparticles was tuned by controlling the pH of the reaction. As prepared ZnSe nanoparticles were spherical in shape, homogeneously distributed in the polymer and XRD patterns exhibit face centred cubic phase. The present method is a novel approach for the synthesis of ZnSe nanoparticles using HPMC as a capping molecule as well as matrix to develop nanocomposite.

Abstract Colloidal quantum dots (QDs) are attracting research interest because of their unique optical properties that result from the quantum confinement effect. ZnSe QDs, which are II–VI semiconductors, offer a wide direct bandgap (2.7 eV), making them promising for applications such as light-emitting diodes, photodetectors, and biomedical labeling. In the present work, colloidal ZnSe (QDs) were synthesized by the hot-injection method with a Zn:Se ratio of 1:1. The optical properties of ZnSe QDs obtained at different reaction times were investigated by spectrophotometric UV–vis absorption and emission measurements. The as-synthesized ZnSe QDs exhibit blue excitonic emission, and no defect emission was detected. Transmission electron micrographs indicated that the QDs have a spherical morphology with dimensions ranging from 3.69 to 4.53 nm. In particular, the Brus model was applied to demonstrate a correlation between the QD sizes and the optical bandgaps obtained from Tauc plots.

As a kind of heavy-metal-free wide bandgap quantum dots (QDs), ZnSe has received extensive attention in the field of blue quantum dots and its light-emitting diodes in recent years. However, there is usually a large lattice mismatch at the core-shell interface of ZnSe based blue quantum dots, where defect states can be easily formed to capture charge carriers and thus deteriorate their optical properties. In this work, ZnSeTe/ZnSe/ZnSeS/ZnS quantum dots with Se/S graded-composition ZnSeS intermediate shells in radial direction were synthesized by replacing the homogeneous single-layer ZnSeS shell with the graded-composition ZnSeS shells. X-ray diffraction, steady-state photoluminescence spectroscopy, time-resolved luminescence spectroscopy, transmission electron microscopy and electroluminescence measurement techniques were used to study the effects of the different intermediate shells on the structure, morphology and optical properties of the synthesized quantum dots. The results show that, all of the synthesized quantum dots emit deep blue light (444. 5 nm) with narrow full widths at half maximum (<18 nm), and they also have uniform size and a zinc blende structure with high crystallinity. As the smoothness of the composition gradient in the ZnSeS intermediate shell along the radial direction is continuously improved, the optical properties such as photoluminescence quantum yield (PLQY) and color purity of the quantum dots are gradually enhanced. Among them, the quantum dots with the linearly graded ZnSeS shells formed by S atom diffusion have the narrowest full width at half maxium (15. 8 nm) and the highest PLQY (20. 7%). The maximum external quantum efficiency and brightness of the light-emitting diode device prepared using the quantum dots with optimal fluorescence performance as emitting materials are 1. 8% and 750 cd/m2, respectively. The quantum dot synthesis scheme and structural optimization strategy proposed in this study may contribute to the development of high-quality non-toxic blue ZnSe based core/shell quantum dots. [ABSTRACT FROM AUTHOR]

Electronic and optical properties of graphene-like ZnSe were investigated through a comprehensive study using ab initio calculations. By employing the GW method, we accurately determine the electronic band structure and bandgap of graphene-like ZnSe, considering the many-body effects. Additionally, we examine the optical properties of graphene-like ZnSe using the GW+BSE method, calculate the optical absorption spectrum, and determine excitonic properties such as exciton binding energy and optical bandgap. The GW calculations reveal that the ZnSe bandgap is direct with an energy gap of approximately 4.869 eV and exhibits excitons with relatively strong binding energies ranging from 0.2 to 0.8 eV. The majority of bound exciton distributions arise from transitions between Zn(3p)+Zn(3d)+Se(4p)→Zn(4s)+Se(4s) at the gamma point of the Brillouin zone. The precise determination of the band structure, bandgap, and excitonic properties enables a better understanding of the material's behavior and aids in the design and optimization of future ZnSe graphene-based devices. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (QDs) are attracting research interest because of their unique optical properties that result from the quantum confinement effect. ZnSe QDs, which are II–VI semiconductors, offer a wide direct bandgap (2.7 eV), making them promising for applications such as light-emitting diodes, photodetectors, and biomedical labeling. In the present work, colloidal ZnSe (QDs) were synthesized by the hot-injection method with a Zn:Se ratio of 1:1. The optical properties of ZnSe QDs obtained at different reaction times were investigated by spectrophotometric UV–vis absorption and emission measurements. The as-synthesized ZnSe QDs exhibit blue excitonic emission, and no defect emission was detected. Transmission electron micrographs indicated that the QDs have a spherical morphology with dimensions ranging from 3.69 to 4.53 nm. In particular, the Brus model was applied to demonstrate a correlation between the QD sizes and the optical bandgaps obtained from Tauc plots. [ABSTRACT FROM AUTHOR]

A review of the state of research in the development of conductometric gas sensors based on II–VI semiconductors is given. It was shown that II–VI compounds indeed have properties that are necessary for the development of highly efficient gas sensors. In this case, to achieve the required parameters, all approaches developed for metal oxides can be used. At the same time, during a detailed review, it was concluded that sensors based on II–VI compounds have no prospects for appearing on the gas sensor market. The main obstacle is the instability of the surface state, which leads to poor reproducibility of parameters and drift of sensor characteristics during operation. [ABSTRACT FROM AUTHOR]

In this work, ZnSe-based polycrystalline ceramics were successfully synthesized from Se and Zn powders in the range of 2.0 GPa and 900 °C–1400 °C by using the high-pressure and high-temperature (HPHT) method. From the acquired experimental results, it was revealed that the fabricated samples were composed of ZnSe with a sphalerite structural type. More specifically, the samples consisted of lamellar and granular grains, and the stomata of the samples showed a trend of first increasing and then decreasing as a function of the elevated temperature. In addition, the infrared transmittance of ZnSe ceramics in the 4 to 18-μm range increased and then decreased by increasing the temperature. When the temperature exceeded the value of 1000 °C, the internal zinc surplus and selenium deficiency of zinc selenide ceramics induced a decrease in the mechanical and optical properties of the ceramics. By optimizing the conditions of the experimental process, the ZnSe synthesized at 1300 °C exhibited better performance with a transmittance of 55%. [ABSTRACT FROM AUTHOR]

The current study explores the prospective of a nitrogen-doped graphene (NG) incorporated into ZnSe-TiO2 composites via hydrothermal method for supercapacitor electrodes. Structural, morphological, and electronic characterizations are conducted using XRD, SEM, Raman, and UV analyses. The electrochemical study is performed and galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) are evaluated for the supercapacitor electrode material. Results demonstrate improved performance in the ZnSe-NG-TiO2 composite, indicating its potential for advanced supercapacitors with enhanced efficiency, stability, and power density. Specific capacity calculations and galvanic charge-discharge experiments confirmed the promising electrochemical activity of ZnSe-NG-TiO2, which has a specific capacity of 222 C/g. The negative link among specific capacity and current density demonstrated the composite's potential for high energy density and high-power density electrochemical devices. Overall, the study shows that composite materials derived from multiple families can synergistically improve electrode characteristics for advanced energy storage applications. [ABSTRACT FROM AUTHOR]

در این مطالعه، سلول خورشیدی CIGS با ساختارMo/CuIn0.7Ga0.3Se2(CIGS) /CdS/ZnO/Al-Doped ZnO توسط نرم افزار Atlas silvaco-TCAD شبیه‌سازی شد. ویژگی‌های فتوولتائیک سلول خورشیدی با استفاده از لایه‌های بافر CdS و ZnSe محاسبه و مقایسه شد. سپس ویژگی‌های فتوولتائیک با ضخامت‌های مختلف لایة بافر ZnSe مورد بررسی قرار گرفت. ضخامت 25 نانومتر به‌عنوان ضخامت بهینه انتخاب شد. پس از بهینه‌سازی ضخامت لایه ZnSe، ویژگی‌های فتوولتائیک سلول خورشیدی با تغییر اختلاف نوار هدایت (CBO) مورد ارزیابی قرار گرفت. بالاترین راندمان تبدیل سلول خورشیدی CIGS در محدوده از eV5/0- تا eV5/0+ برای CBO به‌دست آمد. در نهایت، به‌دلیل شفافیت نوری بالا، تحرک حامل بالا و خواص مکانیکی مناسب، گرافن با Al-doped ZnO (AZO) جایگزین شد. گرافن به‌صورت تک لایه و چند لایه به‌عنوان لایة اکسید رسانای شفاف (TCO) استفاده شد. شبیه‌سازی‌ها بیشترین بازده را برای ساختار سلول خورشیدی بر اساس single layer graphene Mo/CIGS/ZnSe/i-ZnO/ و پارامترهای فتوولتائیک mA/cm2 64/38=Jsc ، V 67/0Voc=، %33/79=FF و 71/20η= درصد پیش بینی کردند.

An ultrathin 15 μm wafer‐based c‐Si solar cell is designed and simulated, wherein the current remedy is done by Cu2SnS3 (CTS) thin film. The ZnSe and AlSb are incorporated as window and back surface field (BSF) layers, respectively, in this model. The ultrathin Si‐based n‐ZnSe/p‐Si exhibits the short‐circuit current density of 30.66 mA cm−2 with an efficiency of 18.80%. The inclusion of p+‐CTS thin film as a second absorber layer has enhanced this current to 42.14 mA cm−2. By absorbing sunlight up to 1200 nm, the CTS layer is able to successfully overcome the constraint of thinner Si wafers on longer‐wavelength photon absorption leading to current augmentation. The addition of p++‐AlSb as the BSF layer also boosts the open‐circuit voltage by 300 mV. The rise in VOC is a result of the larger built‐in potential in ZnSe/Si, Si/CTS, and CTS/AlSb interfaces. With enriched current and voltage, the final proposed n‐ZnSe/p‐Si/p+‐CTS/p++‐AlSb heterostructure theoretically records an efficiency of 35.48% in ultrathin Si solar cells. The current compensation obtained using CTS thin film in this work can give optimism about the future of ultrathin Si solar cells. [ABSTRACT FROM AUTHOR]

Powered by an inexhaustible supply of solar energy, photoelectrochemical (PEC) nitrogen reduction reaction (NRR) provides an ideal solution for the synthesis of green ammonia (NH3). Although great efforts have been made in the past decades, there are still significant challenges in increasing the NH3 yields of the PEC-NRR devices. In addition to the issues of low activity and selectivity similar to electrochemical NRR, the progress of PEC-NRR is also impeded by the limited increase in NH3 yields as the electrode is enlarged. Here, we propose an editable electrode design strategy that parallels unit photo-electrodes to achieve a linear increase in NH3 yields with electrode active area. We demonstrate that the editable electrode design strategy minimizes the electrode charge transfer resistance, allowing more photo-generated carriers to reach the electrode surface and promote the catalytic reaction. We believe that this editable electrode design strategy provides an avenue to achieve sustainable PEC NH3 production. [ABSTRACT FROM AUTHOR]

Nanoparticles of zinc selenide (ZnSe) were produced by an innovative, uncomplicated, and extremely rapid process that took no longer than a few seconds. For the production of zinc ions, zinc chloride was utilized, and selenium was used for the production of selenium ions. The effect of Zn to Se ions ratio on optical properties has been examined. The prepared nanoparticles were tested and characterized by using transmission electron microscope TEM, scanning electron microscope SEM and UV–Visible spectroscopy. The morphological results revealed that the ZnSe has a spherical shape with mean diameter around 15 nm and the band gap of the ZnSe increases with increasing the Zn content in the sample. The prepared materials were tested as antibacterial agent. [ABSTRACT FROM AUTHOR]

In this study, a CIGS solar cell with a Mo/Cu(In0.7Ga0.3)Se2(CIGS)/CdS/ZnO/Al-doped ZnO (AZO) structure was simulated by Atlas silvaco-TCAD software. The photovoltaic characteristics of solar cells using CdS and ZnSe buffer layers were calculated and compared. Then, the photovoltaic characteristics were examined with different thicknesses of the ZnSe buffer layer. The 25 nm thickness was selected as the optimum thickness. After optimization of the ZnSe layer thickness, the photovoltaic characteristics of solar cells were evaluated by changing the conduction band offset (CBO). The highest CIGS solar cell conversion efficiency was obtained in the range from -0.5 eV to +0.5 eV for CBO. Finally, graphene was replaced with Al-doped ZnO (AZO) due to its high optical transparency, high carrier mobility, and proper mechanical properties. Graphene was used as a monolayer and multilayer as a transparent conductive oxide (TCO) layer. Simulations predicted the highest efficiency for solar cell structure based on Mo/CIGS/ZnSe/i-ZnO/monolayer graphene and the photovoltaic parameters were Jsc=38.64 mA/cm², Voc=0.67 V, FF=79.33% and η=20.71%. [ABSTRACT FROM AUTHOR]

Sb2Se3, a promising thin‐film photovoltaic (TFPV) absorber material known for its non‐toxic nature, abundance on Earth, and stability has the inherent limitations of low doping density of 1013 cm−3 and poor carrier mobility of 1.5 cm2 V−1 s−1, leading to a low built‐in potential and inefficient carrier collection. To address these challenges and enhance the built‐in potential and carrier collection, an effective hole‐transport layer (HTL), e.g. CdS, which contains toxic components is used. A less‐toxic alternative is explored: ZnSe as the electron‐transport layer (ETL) to mitigate this issue. In this study, the performance is evaluated of Sb2Se3/ZnSe solar cells using six different HTLs (CuSCN, MoSe2, NiO, Spiro‐OMeTAD, SnS, MoOx) through the utilization of the SCAPS‐1D modeling tool. The HTL plays a critical role in improving the effectiveness of the built‐in potential, enhancing carrier collection, and suppressing back surface recombination. The analysis involves varying the thickness and doping concentration of the absorber, buffer, and HTLs, and exploring the impact of temperature, series and shunt resistance, and the metal work function of the back contact. Among the tested devices, the one with NiO as the HTL demonstrates the highest efficiency, exhibiting a VOC (open‐circuit voltage) of 0.81 V and a PCE (power conversion efficiency) of 24.07%. [ABSTRACT FROM AUTHOR]

Chemical vapor deposition (CVD) ZnS and ZnSe have high infrared transmittance and good optical and mechanical properties, and are the preferred infrared optical materials for infrared military detection systems. The preparation of largesized and highly homogeneous ZnS and ZnSe materials is an important topic for future research. This article introduces the principle of chemical vapor deposition and the main problems in the accumulation process, describes the necessary optical properties of high-performance infrared materials, summarizes and analyzes the research progress of CVD ZnS and CVD ZnSe, and main defect formation mechanism of the two materials as well as the process control research. It aims to improve the production process parameters and provide theoretical reference for the batch preparation of high-performance ZnS and ZnSe materials for military applications. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A review of the state of research in the development of conductometric gas sensors based on II–VI semiconductors is given. It was shown that II–VI compounds indeed have properties that are necessary for the development of highly efficient gas sensors. In this case, to achieve the required parameters, all approaches developed for metal oxides can be used. At the same time, during a detailed review, it was concluded that sensors based on II–VI compounds have no prospects for appearing on the gas sensor market. The main obstacle is the instability of the surface state, which leads to poor reproducibility of parameters and drift of sensor characteristics during operation.

The current study explores the prospective of a nitrogen-doped graphene (NG) incorporated into ZnSe-TiO2 composites via hydrothermal method for supercapacitor electrodes. Structural, morphological, and electronic characterizations are conducted using XRD, SEM, Raman, and UV analyses. The electrochemical study is performed and galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) are evaluated for the supercapacitor electrode material. Results demonstrate improved performance in the ZnSe-NG-TiO2 composite, indicating its potential for advanced supercapacitors with enhanced efficiency, stability, and power density. Specific capacity calculations and galvanic charge-discharge experiments confirmed the promising electrochemical activity of ZnSe-NG-TiO2, which has a specific capacity of 222 C/g. The negative link among specific capacity and current density demonstrated the composite’s potential for high energy density and high-power density electrochemical devices. Overall, the study shows that composite materials derived from multiple families can synergistically improve electrode characteristics for advanced energy storage applications.

Photocatalytic hydrogen production utilizing abundant solar energy to produce high-calorie, clean, and pollution-free hydrogen is an important approach to solving environmental and resource problems. In this work, a high-efficiency flower-like ZnSe/Cu0.08Zn0.92S photocatalyst was constructed through element doping and the formation of a Z-scheme heterojunction. The synergistic effect of Cu doping and the built-in electric field in the heterojunction enhanced light absorption and utilization by the ZnSe/Cu0.08Zn0.92S microflowers, accelerated the separation and transfer of photogenerated electrons and effectively inhibited electron–hole recombination. Thus the photocatalytic hydrogen production ability of the ZnSe/Cu0.08Zn0.92S microflowers was increased significantly. The highly stable ZnSe/Cu0.08Zn0.92S microflowers could provide excellent catalysis of photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

The electronic and magnetic properties of the MnxZn1−xSe system at various impurity atom (Mn) concentrations were investigated using first-principle calculations. The computed values of formation energies were found negative for different manganese concentrations which demonstrate the stability of the investigated systems. For this reason, the ferromagnetic and the antiferromagnetic states are studied for different impurity atom concentrations. The density of states calculations for spin-up and spin-down states show asymmetric which displays the paramagnetic nature of the Mn-doped ZnSe system. The obtained value of the total magnetic moment for different supercells was found 5.0 µB/Mn. A half-metallic state is observed in the presence of Zn vacancy in Mn:ZnSe system. [ABSTRACT FROM AUTHOR]

The paper presents the results on the development of an optical coating for a single-crystal ZnGeP2 substrate based on a selenide-oxide pair of materials (ZnSe/Al2O3). The obtained coating ensures the operation of OPO in the mid-IR range up to 5 μm wavelengths. The possibility of ZnSe sputtering by the IBS method is shown. The obtained optical coating has a high laser-induced damage threshold (LIDT) value at a 2097 µm wavelength: WoE=3.51 J/cm2 in energy density and WoP= 101 W/cm2 in power density at a 10 KHz pulse repetition frequency and a pulse duration of 35 ns. Thus, it is shown for the first time that the pair of materials ZnSe/Al2O3 can be used for the deposition of optical coatings by the IBS method with high LIDT values for ZnGeP2 optical elements operating in the mid-IR range.

The physical properties of nanocrystalline systems of cadmium and zinc selenides have been studied experimentally and theoretically. The effect of temperature and various gaseous media on the specific conductivity of films of cadmium and zinc selenides has been experimentally studied. The values of the Fermi energy, the concentration of donor charge carriers in the conduction band, the activation energy of donors, and the temperature coefficient of resistance are theoretically calculated. It is shown that the calculated values correlate with the experimental ones, which will make it possible to predict the stability of the operation of semiconductor devices.

Electrochemical reduction reaction of nitrogen (NRR) offers a promising pathway to produce ammonia (NH3) from renewable energy. However, the development of such process has been hindered by the chemical inertness of N2. It is recently proposed that hydrogen species formed on the surface of electrocatalysts can greatly enhance NRR. However, there is still a lack of atomic-level connection between the hydrogenation behavior of electrocatalysts and their NRR performance. Here, we report an atomistic understanding of the hydrogenation behavior of a highly twinned ZnSe (T-ZnSe) nanorod with a large density of surface atomic steps and the activation of N2 molecules adsorbed on its surface. Our theoretical calculations and in situ infrared spectroscopic characterizations suggest that the atomic steps are essential for the hydrogenation of T-ZnSe, which greatly reduces its work function and efficiently activates adsorbed N2 molecules. Moreover, the liquid-like and free water over T-ZnSe promotes its hydrogenation. As a result, T-ZnSe nanorods exhibit significantly enhanced Faradaic efficiency and NH3 production rate compared with the pristine ZnSe nanorod. This work paves a promising way for engineering electrocatalysts for green and sustainable NH3 production. [ABSTRACT FROM AUTHOR]

Polycrystalline zinc selenide (ZnSe) and Cr2+ or Fe2+ doped ZnSe are key optical elements in mid-infrared laser systems. The laser-induced damage of the optical elements is the limiting factor for increasing the power and pulse energy of the lasers. In the present work, the optical damage of the ZnSe, Cr2+:ZnSe, and Fe2+:ZnSe samples induced by a repetitively pulsed Ho3+:YAG laser at 2091 nm was studied. The probability of the optical damage and the laser-induced damage threshold (LIDT) were determined for the samples manufactured using different processing techniques. The highest LIDT was found in ZnSe samples annealed in an argon atmosphere. It was also found that the samples annealed in a zinc atmosphere or with hot isostatic pressing resulted in a decrease in the LIDT. The Cr2+-doped ZnSe had the lowest LIDT at 2.1 µm compared to Fe2+-doped or undoped ZnSe. The LIDT fluence of all tested ZnSe samples decreased with the increase in the pulse repetition rate and the exposure duration. The results obtained may be used to improve the treatment procedures of ZnSe, Cr2+:ZnSe, and Fe2+:ZnSe polycrystals to further increase their LIDT.