Investigation of GeSe Photovoltaic Device Performance via 1-Dimensional Computational Modelling

Abstract

Germanium selenide (GeSe) is a potential absorber material for thin film solar cells. However, many physical, electronic parameters and practical defect configurations that result in different effects on the performance of GeSe solar cells are not fully understood. In this study, a baseline of a GeSe thin film solar cell was designed and simulated using SCAPS-1D simulator. The physical and electronic parameters of the absorber layer is varied to investigate their effect on the performance of the solar cell. The simulation uses absorption files extracted from Xue et al. 2016 and the SCAPS-1D absorption model. Practical defect configurations are also introduced in GeSe thin film solar cells to optimize solar cell performance. Simulation results show that baseline GeSe solar cells had obtained Voc 0.62 V, Jsc 39.52 mA/cm<sup>2</sup>, FF 79.34 and ƞ 19.48%. Simulation using the SCAPS-1D absorption model achieved a more accurate JSC contour graph compared to simulation using absorption files extracted from Xue et al. 2016. The highest efficiency of 26.13% was achieved at 1.40 eV bandgap, 4.27 eV electron affinity, 10 cm2/Vs hole mobility, 1E+18 1/cm<sup>3</sup> hole concentration and 2000 nm GeSe layer thickness. For bulk defect, an increase in defect concentrations or capture cross section hole and electron (σ) reduce efficiency. For interfacial defect GeSe/CdS, total density of 1E+12 1/cm<sup>2</sup> with σ of 1E-13 cm<sup>2</sup>, total density of 1E+18 1/cm2 with σ of 1E-19 cm<sup>2</sup>, total density of 1E+16 1/cm<sup>2</sup> and 1E+18 1/cm<sup>2</sup> with σ of 1E-16 cm<sup>2</sup> have critical impact to solar cell.