Realization of High Photovoltaic Efficiency Devices With Sb₂S₃ Absorber Layer

This study investigates the impact of substrate temperature ( ${T}_{\text {sub}}{)}$ on the structural, optical, and electrical properties of dual ion beam sputtering (DIBS)-grown Sb2S3 thin films. ${T}_{\text {sub}}$ has been systematically varied from room temperature (RT) to 300 °C. X-ray diffraction (XRD) investigation demonstrates the high crystalline quality of the Sb2S3 thin films, revealing an orthorhombic structure with a characteristic diffraction peak corresponding to (211) plane observed at 28.4°. The field-emission scanning electron microscopy (FESEM) images illustrate that the growth of thin film at 200 °C yields the largest grain size, measuring 62 nm, along with homogeneous and distinct grain morphology. In-depth optical analysis using spectroscopic ellipsometry (SE) with a three-layer model fitting technique indicates a high absorption coefficient ( $10^{{5}}$ cm $^{-{1}}{)}$ in the UV–VIS spectral region, while the films exhibit direct bandgap values ranging from 1.6 to 2.3 eV. The electrical resistivity and mobility of the Sb2S3 films are evaluated at RT through four-probe Hall measurements, confirming the stable, repeatable, and reliable p-type electrical conductivity. In addition, the analysis of the p-Sb2S3/n-Si junction demonstrates an exceptional rectification ratio of 100 at ±1 V. Furthermore, the experimental results are incorporated into the modeling and numerical analysis of Sb2S3 heterojunction solar cells using the solar cell capacitance simulator (SCAPS) software. This analysis has identified the optimal thickness for the Sb2S3 absorber layer to be $1.5~\mu \text{m}$ , resulting in the highest efficiency of 16.39% along with open-circuit voltage ( ${V}_{\text {oc}}{)}$ of 0.949 V, short-circuit current ( ${J}_{\text {sc}}{)}$ of 24.73 mA/cm2, and fill factor (FF) of 69.81%.