Improving the efficiency of ZnTe based heterojunction solar cell with In2Te3 BSF layer

Abstract

Zinc telluride (ZnTe) is considered as a favorable photovoltaic (PV) material for its desirable absorption coefficient, improved conversion efficiency, and consequently inexpensive production material requirements. The unsuitability of the solar cell structure and band alignment at the buffer/absorber and absorber/BSF interface as well as carrier recombination at the front and back metal contact prevents the probable result from being achieved. The principal objective of this research is to improve the performance of newly designed Al/ZnO/CdS/ZnTe/In2Te3/Pt solar cell and to investigate the influence of the Indium telluride (In2Te3) back surface field (BSF) layer on the performance parameters of open circuit voltage (Voc), short circuit current (Jsc), fill factor (FF), and power conversion efficiency (PCE). This simulation analyses the performance of the baseline structure Al/ZnO/CdS/ZnTe/Pt which is consider as without BSF and the proposed structure Al/ZnO/CdS/ZnTe/In2Te3/Pt which is consider as with BSF. The thickness, carrier density and bulk defect density of every layer, defect density at BSF/absorber and buffer/absorber interface, working temperature, back surface recombination velocity (SRV) as well as shunt and series resistance has been studied using SCAPS-1D simulator. The PCE has been achieved 20.20% with VOC of 2.008 V, JSC of 10.99 mA/cm2 and FF of 91.92% for the proposed solar cell with In2Te3 BSF layer by using thicknesses of around 30 nm, 30 nm, 500 nm and 100 nm for ZnO, CdS, ZnTe, and In2Te3, respectively. The present study provides the guidelines for the realization of high efficiency and thin ZnTe based solar cell in cost effective way.