Design and simulation of double-heterojunction solar cells based on Si and GaAs wafers

Abstract

This article demonstrates the novel designs of Si and Ga As wafer-based double-heterojunction (DH) solar cells using SCAPS-1Dsimulator. Simple five-layer solar cells are proposed here: cells comprised of a cathodemetal layer, three layers of semiconductor materials in the III-V, II-VI and group IV families-and a layer of anode metal. The device structures have been optimized for the analysis of the power-conversion efficiency (PCE) of the Si and GaAs solar cells considering high defect densities at and near each heterojunction. The PCEs predicted are 38%and 38.9%for n-ZnSe/p-Si/p+-Al0.8Ga0.2Sb and n-ZnSe/p-GaAs/p+-AlAs0.9Sb0.1 cells, respectively which stay entirely within the PCE limits set by the Shockley-Queisser theory of multi-junction cell. These results reveal that high efficiency and hence cost-effective Si and Ga As wafer-based DH solar cells can be fabricated in the near future.