ZnSe Layers Research Articles

Innovative Type-II ZnSe/InSSe heterojunction: Photocatalytic properties and strain modulation from first-principles calculations

In this study, we propose an innovative type-II ZnSe/InSSe heterojunction for efficient photocatalytic water-splitting. This heterojunction exhibits a direct band gap of 1.9 eV and staggered band alignment, which efficiently separates photogenerated carriers, facilitating overall water-splitting. The built-in electric field drives electrons to accumulate in the InSSe layer and holes accumulate in the ZnSe layer, thereby suppressing recombination and enhancing photocatalytic efficiency. The solar-to-hydrogen efficiency reaches 8.92 %. Furthermore, the electronic and optical properties of ZnSe/InSSe heterojunction can be modified by biaxial strain, with tensile strain significantly improving visible light absorption and overall efficiency. Under tensile strain, the band gap decreases, enhancing the light absorption capability in the visible range, which further boosts the photocatalytic performance. Our findings demonstrate the ZnSe/InSSe heterojunction as a promising candidate for high-efficiency photocatalytic hydrogen production, offering valuable insights for future photocatalyst development. This research provides a potential pathway to optimize semiconductor heterojunctions for sustainable energy applications through strain engineering.

A Comprehensive Study on Structural and Optical Properties of Zinc Selenide/Poly Ortho-methoxyaniline Hybrid Thin Films Deposited by Chemical Bath Deposition and Plasma Polymerization Techniques

Hybrid thin films hold dominant importance in various technological applications due to their synergistic effects between inorganic and organic materials. In this study, inorganic–organic hybrid thin film has been produced where the inorganic layer of zinc selenide (ZnSe) is deposited first through chemical bath deposition technique and the organic layer is deposited onto the inorganic layer using a capacitively coupled plasma polymerization technique. The ZnSe layer deposited for one hour has been used as the base layer and plasma polymerized (PP) o-methoxyaniline (OMA) has been deposited for different deposition durations. The experimental results showed that thickness of the the hybrid films increases with the organic layer deposition time. The field emission scanning electron microscope exhibited a large number of pores on the surface of the ZnSe film, which are significantly covered up when organic PPOMA is deposited onto it. The energy-dispersive X-ray confirms the constitutional elements of the hybrid films and X-ray diffraction study indicates the enhancement of crystallinity of the film. Differential scanning calorimetry and thermogravimetric analysis specify that hybrid films are thermally more stable (up to 396 °C) compared to pure ZnSe film (351 °C), probably due to higher conjugation in the PP organic layer. The direct optical band gaps of the deposited hybrid thin films are found to increase from 2.4 to 2.80 eV with the increase of organic layer onto ZnSe film. Consequently, the Urbach energy decreases from 0.94 to 0.66 eV with the deposition of hybrid film for different time durations. The outcomes of this study suggest that the hybrid films would have enormous potential as passive thin films for photovoltaic cells, sensing and optical devices.

Unveiling the Role of Ge in CZTSSe Solar Cells by Advanced Micro-To-Atom Scale Characterizations.

Kesterite is an earth-abundant energy material with high predicted power conversion efficiency, making it a sustainable and promising option for photovoltaics. However, a large open circuit voltage Voc deficit due to non-radiative recombination at intrinsic defects remains a major hurdle, limiting device performance. Incorporating Ge into the kesterite structure emerges as an effective approach for enhancing performance by manipulating defects and morphology. Herein, how different amounts of Ge affect the kesterite growth pathways through the combination of advanced microscopy characterization techniques are systematically investigated. The results demonstrate the significance of incorporating Ge during the selenization process of the CZTSSe thin film. At high temperature, the Ge incorporation effectively delays the selenization process due to the formation of a ZnSe layer on top of the metal alloys through decomposition of the Cu-Zn alloy and formation of Cu-Sn alloy, subsequently forming of Cu-Sn-Se phase. Such an effect is compounded by more Ge incorporation that further postpones kesterite formation. Furthermore, introducing Ge mitigates detrimental "horizontal" grain boundaries by increasing the grain size on upper layer. The Ge incorporation strategy discussed in this study holds great promise for improving device performance and grain quality in CZTSSe and other polycrystalline chalcogenide solar cells.

Investigation of suitable buffer layer for PbS-TBAI/PbS-EDT colloidal quantum dot solar cell using SCAPS-1D

Colloidal quantum dots (CQD) are emerging third-generation photovoltaic technologies because of their ability to link a wider range of the light spectrum compared to those of perovskite, crystalline, and copper indium gallium selenide (CIGS) solar cells. In this work, a Lead Sulphide (PbS) CQD solar cell architecture with Ag2S, CdS, ZnSe and ZnS buffer layer is presented. The device consisting of PbS-tetrabutyle ammonium iodide (PbS-TBAI) as an absorber layer, PbS-1,2-ethanedithiol (PbS-EDT) as a hole transport layer (HTL), TiO2 as an electron transport layer (ETL), and fluorine tin oxide (FTO) as an oxide layer. The electrical performances of the solar cells were simulated using SCAPS-1D while taking into account different buffer layers with increasing bandgap values. With ZnS acting as a buffer layer, the computational modelling and analysis of architectural PbS CQD solar cell result in an efficiency of 17.12%. Additionally, the parameters of the solar cell have been studied to be affected by the thickness and bandgap of the absorber and HTL layers, the effect of acceptor concentration with various buffer layers, the impact of temperature, the effect of HTL doping density, and the effect of absorber layer defect density. This study can serve as a guide for future PbS CQD solar cells.

Simulation and performance analysis of CdTe thin film solar cell using different Cd-free zinc chalcogenide-based buffer layers

In this study, the performance of a Cadmium Telluride (CdTe) thin-film solar cell was evaluated with various buffer layers (CdS, ZnSe, ZnO, ZnS) using the Silvaco-Atlas semiconductor device simulator. The impact of these buffer layers on the functionality of the CdTe solar cell was scrutinized at a temperature of 300 K under standard AM1.5G illumination. Initially, the modeling and simulation results of CdS/CdTe solar cell were examined, in comparison with the experimental and simulation results previously reported, to validate our reference structure and to explore its performance. The baseline CdS/CdTe solar cell, serving as a benchmark, yielded a conversion efficiency of 22.14 %. Then we attempted to identify an environmentally friendly alternative buffer layer for the CdTe thin film solar cell by substituting CdS with various Cd-free zinc chalcogenide-based materials (Zn(O,S,Se)) to boost efficiency. By trimming the layer thickness to approximately 0.01 μm, conversion efficiencies of 23.04 %, 23.13 % and 24.48 % were attained for the ZnO, ZnSe, and ZnS buffer layers, respectively. In order to investigate the performance of each proposed structure, thickness and doping density of the absorber and buffer layer were varied. Best efficiency around 25.23 % and 25.04 % are achieved for the optimized solar cells for ZnS and ZnSe buffer layer, respectively. As a result, ZnS and ZnSe are promising materials can be used as an alternative to the commonly used CdS buffer layer in CdTe solar cell. The influence of the operating temperature on solar cell performance was also investigated.

Crystal Orientation Engineering of Perfectly Matched Heterogeneous Textured ZnSe for an Enhanced Interfacial Kinetic Zn Anode.

Uncontrollable dendrite formation in the Zn anode is the bottleneck of the commercialization of rechargeable aqueous zinc-based batteries (RAZBs). Interface, the location of the charge transfer process occuring, can significantly affect the further morphology evolution in ways that have not yet been fully comprehended, for example, the crystal facet and orientation of the coating layer. In this study, we demonstrated that the morphology and kinetics of the Zn anode could be tuned by the crystal facet. The fabricated textured ZnSe (T-ZnSe) layer can significantly enhance the reaction kinetics and induce uniform (0002)Zn deposition. In stark contrast, the polycrystalline P-ZnSe coating hinders the charge transfer process at the interface. With this T-ZnSe@Zn as the anode, the full cell with an I2 cathode and a practical areal capacity (2 mAh cm-2) can work well for 900 cycles. The effectiveness of this anode has also been testified by a pouch cell with an overall capacity of 150 mAh. This research contributes to the understanding of the interface and the feasible strategy for the practical application of the Zn anode.

Tuning the Shades of Red Emission in InP/ZnSe/ZnS Nanocrystals with Narrow Full Width for Fabrication of Light-Emitting Diodes.

While Cd-based luminescent nanocrystals (NCs) are the most mature NCs for fabricating efficient red light-emitting diodes (LEDs), their toxicity related limitation is inevitable, making it necessary to find a promising alternative. From this point of view, multishell-coated, red-emissive InP-based NCs are excellent luminescent nanomaterials for use as an emissive layer in electroluminescent (EL) devices. However, due to the presence of oxidation states, they suffer from a wide emission spectrum, which limits their performance. This study uses tris(dimethylamino)phosphine (3DMA-P) as a low-cost aminophosphine precursor and a double HF treatment to suggest an upscaled, cost-effective, and one-pot hot-injection synthesis of purely red-emissive InP-based NCs. The InP core structures were coated with thick layers of ZnSe and ZnS shells to prevent charge delocalization and to create a narrow size distribution. The purified NCs showed an intense emission signal as narrow as 43 nm across the entire red wavelength range (626-670 nm) with an emission quantum efficiency of 74% at 632 nm. The purified samples also showed an emission quantum efficiency of 60% for far-red wavelengths of 670 nm with a narrow full width of 50 nm. The samples showed a relatively long average emission lifetime of 50-70 ns with a biexponential decay profile. To demonstrate the practical ability of the prepared NCs in optoelectronics, we fabricated a red-emissive InP-based LEDs. The best-performing device showed an external quantum efficiency (EQE) of 1.16%, a luminance of 1039 cd m-2, and a current efficiency of 0.88 cd A-1.

Zinc selenide based dual-channel SPR optical biosensor for HIV genome DNA hybridization detection

Simultaneous measurement of human immunodeficiency virus (HIV) genome DNA hybridization and the DNA melting temperature in a prism-based surface plasmon resonance (SPR) biosensor is modeled theoretically using a simple dual-channel construction. The proposed sensor consists of a BK7 prism coated with silver as a plasmonic material. The metal surface is divided into two channels to detect medium refractive index (RI) and temperature. One half is covered with zinc selenide (ZnSe) semiconductor to enhance the hybridization detection sensitivity and to protect silver from oxidation. The other half is covered with polydimethylsiloxane (PDMS) polymer to detect the temperature variations. The proposed sensor is optimized numerically, and the optimum structure provides an excellent sensitivity of 208 deg/RIU, thanks to the use of the ZnSe layer, which is greater than double the reported dual-channel prism-based sensor in thickness. The polymer channel shows high sensitivity to the temperature variations of − 0.125 deg/°C, which is nearly 10 times the response of the RI channel to temperature variations. The data obtained from the polymer channel is used to compensate for the thermal perturbations of the sensing medium RI, and at the same time, to monitor the increments of the temperature in order to avoid reaching the DNA melting temperature. A mathematical expression is provided to consider the effect of the temperature variations on the RI of the sensing medium to get a better accurate detection process. The DNA hybridization detection of HIV is theoretically discussed in detail starting from the preparation of the sensing medium with the different ingredients until the hybridization between probe and complementary target DNA (ct-DNA) molecules.

Numerical assessment of optoelectrical properties of ZnSe–CdSe solar cell-based with ZnO antireflection coating layer

In this work, a numerical assessment of the optoelectrical properties of the ZnO–ZnSe–CdSe heterojunction for a thin and cost-effective solar cell was made by using the PC1D simulation software. The photovoltaic (PV) properties have been optimized by varying thicknesses of the absorber layer of the p-CdSe layer, the window layer of n-ZnSe, and the antireflection coating (ARC) layer of ZnO, a transparent conductive oxide with enhanced light trapping, and wide bandgap engineering. There is a positive conduction band offset (CBO) of ΔEc = 0.25 eV and a negative valence band offset (VBO) of ΔEv = 1.2 − 2.16 = − 0.96 eV. The positive CBO prevents the flow of electrons from the CdSe to the ZnSe layer. Further, the impact of doping concentration on the performance of solar cells has been analyzed. The simulation results reveal the increase in the efficiency of solar cells by adding an ARC. The rapid and sharp increase in the efficiency with the thickness of the window layer beyond 80 nm is interesting, unusual, and unconventional due to the combined effect of morphology and electronics on a macro-to-micro scale. The thin-film solar cell with the structure of ZnO/ZnSe/CdSe exhibited a high efficiency of 11.98% with short-circuit current (Isc) = 1.72 A, open-circuit voltage (Voc) = 0.81 V and fill factor (FF) = 90.8% at an optimized thickness of 2 μm absorber layer, 50 nm window layer, and 78 nm ARC layer. The EQE of solar cells has been observed at about 90% at a particular wavelength at 470 nm (visible light range). Around 12% of efficiency from such a thin-layered solar cell is highly applicable.

Polarization- and angle-insensitive broadband long wavelength infrared absorber based on coplanar four-sized resonators.

In many potential applications, there is a high demand for long wavelength infrared (LWIR) absorbers characterized by a compact configuration, broad operational bandwidth, high absorption efficiency, and polarization- and angle-insensitive characteristics. In this study, we design and demonstrate a high-performance broadband LWIR absorber based on coplanar four-sized resonators, consisting of arrays of titanium (Ti) disks with different diameters supported by a continuous zinc selenide (ZnSe) layer and by a Ti film acting as a back-reflector. Particle swarm optimization (PSO) is employed to optimize the complicated geometry parameters, and the final optimized device exhibits near-unity absorption (∼96.7%) across the entire operational bandwidth (8 µm∼14 µm) under unpolarized normal incidence, benefiting from the impedance-matching condition and the multiple surface plasmon resonances of this configuration. Furthermore, the proposed absorber is insensitive to the angle of incidence due to the localized surface plasmon resonances supported by these four-sized resonators, and is insensitive to the state of polarization thanks to the highly symmetric feature of the circular pattern. The measured absorption of the fabricated sample exhibits a relatively high coincidence with the simulation, with an average absorption of 88.9% ranging from 8 µm to 14 µm. The proposed absorber, which can be easily integrated into a standardized micro/nano manufacture process for cost-effective large-scale production, provides a feasible solution for improving optical performance in thermal emitter, infrared detection, and imaging applications. Furthermore, the generalized design principle employing the optimized method opens up new avenues for realizing target absorption, reflection, and transmission based on more complicated structure configurations.

Investigation of CdSe and ZnSe as Potential Back Surface Field Layers for CdTe‐Based Solar Cells: A Study from First Principles Calculations

AbstractA class of II–VI semiconductors, especially CdTe, is a highly photo‐reactive compound that would be suitable for photovoltaic applications. However, being a highly resistive material, CdTe produces considerable contact resistance and drastically reduces the efficiency of photovoltaic devices. Introducing a back surface field layer at the contact region may significantly improve the device's performance. This work investigates the suitability of using ZnSe and CdSe layer as a back‐surface‐field layer in CdTe‐based solar cells through accurate electronic structure calculations using the hybrid‐density functional theory method. The calculations show that both ZnSe/CdTe and CdSe/CdTe behave as type‐II heterojunctions with band gaps of 2.0 and 1.1 eV, respectively. The Mulliken electronegativity method is used to determine the correct band edge positions concerning the vacuum level for all the pristine semiconductors and their interfaces. Calculation shows that a significant charge redistribution in the interface leads to the formation of an effective local field near the contact region for both ZnSe/CdTe and CdSe/CdTe heterostructures. This local field may help to separate the photogenerated electron–hole pairs in the active layer by pushing the opposite charges into the two different sections of the heterojunction. Additionally, the heterojunctions also exhibit better light‐absorption characteristics in the visible light range.

Fabrication and characterization of ZnS and ZnSe absorber layers for UV-selective transparent photovoltaics

We have fabricated ZnS, ZnSe and mixed Zn(S,Se) thin film layers for application as solar cell absorbers in ultraviolet (UV)-selective solar cells. We fabricated the thin film layers using a two-step process involving evaporation of the Zn layer followed by an anneal in an H2S and/or H2Se containing atmosphere. A study of the annealing conditions was performed to minimize hole formation in the thin film layer. A mixed Sulfur and Selenium containing layer was also developed in order to reach a 3 eV band gap, such that the layer absorbs all the UV light and leaves the visible light passing through. Next, we tried to increase the conductivity of the layer by adding extrinsic doping elements. Cu was found to increase the conductivity by more than three orders of magnitude, while leaving the transparency of the layer mostly unchanged. Finally, solar cell devices were fabricated using transparent back and front contacts and a NiO buffer layer. We could measure a very small photocurrent of about 100 μA/cm2 and an open circuit voltage of about 500 mV under AM1.5 G illumination.

The effects of deposition manner and rate on structure and morphology of porous ZnSe nanolayers: Modification of Phonon Confinement Model for resonant Raman conditions

Nanolayers of porous ZnSe with thickness of ∼50 nm were prepared by thermal vacuum evaporation, applying continuous and periodically interrupted deposition at different deposition rates. The surface morphology and film composition are studied by SEM and EDS methods. The XRD and Raman scattering measurements are used to confirm zinc blende ZnSe crystal structure. The Phonon confinement model is modified to analyze the Raman spectra excited by different laser lines both in non-resonant and near-resonant conditions. This analysis provides more profound insight in the ZnSe layers composition, nanocrystallite size and crystal lattice strain. The Raman results are also supported by the spectroscopic ellipsometry regarding the energy gap and porous properties of ZnSe layers. This study shows that both manner and rate of deposition significantly affect the nanolayers structure, morphology and optical properties and provide preparation of films with properties suitable for application which requires specific porous parameters important for the films chemical sensitivity.

Influence of Annealing Temperature on the Properties of SILAR Deposited CdSe/ZnSe Superlattice Thin Films for Optoelectronic Applications

In this work, superlattice thin films of CdSe/ZnSe were fabricated on a non-conductive glass substrate using the successive ionic layer adsorption reaction (SILAR) method to investigate their properties for possible optoelectronic applications. The SILAR process involved a total cycle time of 100 seconds for a complete SILAR cycle with a total of 12 cycles made by depositing alternative layers of CdSe and ZnSe. The deposited thin films were annealed at different temperatures and characterized to determine their optical, elemental, morphological and structural properties using UV-VIS spectroscopy, Scanning electron microscope (SEM)/energy dispersive x-ray spectroscope (EDS) and x-ray diffraction techniques (XRD). The results of the characterizations revealed that optical properties of the films such as absorbance, reflectance, refractive index and extinction coefficient are low but increased as the annealing temperature increases. The bandgap energy was found to decrease from 2.50 eV-1.90 eV for as-deposited film and those annealed between 373 K and 523 K. film thickness was found to range from 130.169 nm to 254.441 nm. The EDS results showed that the target elements such as Cd, Zn, Se and other elements traceable to the nature of substrate used were found to be present in the deposited thin film samples. The results of the XRD showed that the thin films are polycrystalline and the diffraction peaks are influenced by annealing of the sample at a higher temperature such as 523 K. The crystal parameters such as crystallite size, dislocation density and micro-strain of the film at 523 K were found to be 5.546 nm, 3.25 × 1016 l/m2 and 1.13 × 10-2. The SEM results showed that the CdSe/ZnSe superlattice films were composed of tiny nanoparticles of different dimensions and sizes with hollow which increased as the annealing temperature increased from 432 K to 523 K. Possible applications of the deposited superlattice thin films in solar cells and optoelectronic devices were established by virtue of their bandgap energy and other properties.

Spectra Stable Quantum Dots Enabled by Band Engineering for Boosting Electroluminescence in Devices

The band level landscape in quantum dots is of great significance toward achieving stable and efficient electroluminescent devices. A series of quantum dots with specific emission and band structure of the intermediate layer is designed, including rich CdS (R-CdS), thick ZnSe (T-ZnSe), thin ZnSe (t-ZnSe) and ZnCdS (R-ZnCdS) intermediate alloy shell layers. These quantum dots in QLEDs show superior performance, including maximum current efficiency, external quantum efficiencies and a T50 lifetime (at 1000 cd/m2) of 47.2 cd/A, 11.2% and 504 h for R-CdS; 61.6 cd/A, 14.7% and 612 h for t-ZnSe; 70.5 cd/A, 16.8% and 924 h for T-ZnSe; and 82.0 cd/A, 19.6% and 1104 h for R-ZnCdS. Among them, the quantum dots with the ZnCdS interlayer exhibit deep electron confinement and shallow hole confinement capabilities, which facilitate the efficient injection and radiative recombination of carriers into the emitting layer. Furthermore, the optimal devices show a superior T50 lifetime of more than 1000 h. The proposed novel methodology of quantum dot band engineering is expected to start a new way for further enhancing QLED exploration.

Tunable multi-channel optical filters based on Octonacci one-dimensional photonic quasicrystals

We propose a structure for a tunable multi-channel optical filter based on a one-dimensional quasicrystal made up of ZnSe (layer H) and ZnS (layer L) layers organized following the Octonacci sequence. The fourth stage of the sequence, S4, is considered here with initial conditions S1 = L and S2 = H giving the multi-layered system a structure of HLHHHLH. The transmittance spectrum of the s-polarized (transverse electric mode) light is obtained analytically by employing a theoretical calculation based on the transfer matrix method. For normally incident waves, four output signals are transmitted out from the structure. The transmitted signals move to shorter wavelengths as the angle of incidence increases up to 89 deg. At this angle of incidence, the output signals exhibit narrow, sharp, and well-defined resonant peaks. On the other hand, the resonant peaks shift to longer wavelengths as the ambient temperature increases from room temperature to 500°C. The obtained results reveal that the proposed structure could be used as an efficient multi-channel optical filter. The overall dimension of the proposed structure is about 569 nm, which practically makes the filter easily integrated into photonic circuits.

Self‐Healing SeO2 Additives Enable Zinc Metal Reversibility in Aqueous ZnSO4 Electrolytes

AbstractThe development of aqueous zinc metal batteries (AZMBs) is significantly impeded by the poor cycle stability of Zn anodes due to the uncontrolled dendrite growth and low Coulombic efficiency (CE). Herein, for the first time, SeO2 additives are introduced into ZnSO4 electrolyte to enhance the stability of the Zn anode. According to the experimental results, the protective ZnSe layer is initially in‐situ formed on the Zn surface prior to the Zn plating, which acts as a shield for inhibiting the parasitic reactions and dendrite formation. Moreover, this additive strategy yields the unique characteristic of self‐healing for recovering the cracks in the consequence of huge volume change, ensuring the durability of ZnSe layer. Consequently, Zn|Zn symmetric cell using SeO2 additive delivers an enhanced cumulative plated capacity of 2.1 Ah cm−2 under practical test conditions, which far exceeds the previously reported works. Meanwhile, the average CE of 99.6% for 250 cycles is also demonstrated in Zn|Cu half cells with the presence of the SeO2 additive. In addition, the positive effect of the SeO2 additive is further illustrated in the Zn‐MnO2 full cells with a limited Zn.

Change in structure and luminescent properties of ZnSe and ZnCdSe films irradiated by electron beam

Layers of ZnSe and ZnCdxSe (x ~ 0.32-0.35) grown on GaAs (001) substrates by molecular beam epitaxy method were investigated. The electron beam impact on changes in crystal structure of specimens under examination and on their luminescent properties was studied. Methods of cathode luminescence, transmission electron microscopy, and electron microprobe analysis were applied. It is found that irradiation of specimens in the transmission electron microscope results in stacking faults annealing accompanied by formation of ZnO precipitates with hexagonal crystal structure. Irradiation of specimens in the cathode luminescence plant results in decreased intensity of cathode luminescence layers of ZnSe and ZnCdxSe in question due to radiation-stimulated degradation processes. Key words: point defects, irradiation by electron beam, cathode luminescence, structural changes.

Design of a highly efficient FeS2-based dual-heterojunction thin film solar cell

ABSTRACT This article demonstrates a highly efficient FeS2-based n-ZnSe/p-FeS2/p+-AlxGa1-xSb dual-heterojunction thin film solar cell using SCAPS-1D simulator. The study has been carried out taking the physical parameters from the literature. The influence of thickness, doping, and defect concentration of ZnSe, FeS2, and AlxGa1-xSb layers on the photovoltaic performance of the solar cell has been investigated in details. The power conversion efficiency (PCE) of the n-ZnSe/p-FeS2 single-heterojunction solar cell is ~23.22% with JSC = 47.52 mA/cm2, VOC = 0.59 V, and FF = 82.62%, respectively. The PCE of the solar cell further increases to ~36.75% with JSC = 48.13 mA/cm2, VOC = 0.94 V, and FF = 80.75%, respectively with the insertion of AlxGa1-xSb back surface field (BSF) layer. This increase in PCE is mainly due to the enhancement of VOC which is resulted from the suitable band alignment of the dual-heterojunction devices. These results indicate that FeS2-based dual-heterojunction thin film solar cell with ZnSe and AlxGa1-xSb window and BSF layers, respectively, is a potential candidate to fabricate high efficiency thin film solar cell for harvesting solar energy in the future.

Numerical Modelling Analysis for Carrier Concentration Level Optimization of CdTe Heterojunction Thin Film–Based Solar Cell with Different Non–Toxic Metal Chalcogenide Buffer Layers Replacements: Using SCAPS–1D Software

Cadmium telluride (CdTe), a metallic dichalcogenide material, was utilized as an absorber layer for thin film–based solar cells with appropriate configurations and the SCAPS–1D structures program was used to evaluate the results. In both known and developing thin film photovoltaic systems, a CdS thin–film buffer layer is frequently employed as a traditional n–type heterojunction partner. In this study, numerical simulation was used to determine a suitable non–toxic material for the buffer layer that can be used instead of CdS, among various types of buffer layers (ZnSe, ZnO, ZnS and In2S3) and carrier concentrations for the absorber layer (NA) and buffer layer (ND) were varied to determine the optimal simulation parameters. Carrier concentrations (NA from 2 × 1012 cm−3 to 2 × 1017 cm−3 and ND from 1 × 1016 cm−3 to 1 × 1022 cm−3) differed. The results showed that the use of CdS as a buffer–layer–based CdTe absorber layer for solar cell had the highest efficiency (%) of 17.43%. Furthermore, high conversion efficiencies of 17.42% and 16.27% were for the ZnSe and ZnO-based buffer layers, respectively. As a result, ZnO and ZnSe are potential candidates for replacing the CdS buffer layer in thin–film solar cells. Here, the absorber (CdTe) and buffer (ZnSe) layers were chosen to improve the efficiency by finding the optimal density of the carrier concentration (acceptor and donor). The simulation findings above provide helpful recommendations for fabricating high–efficiency metal oxide–based solar cells in the lab.