SCAPS-1D Numerical Simulation of Homojunction and Heterojunction ZnO/Si Solar Cells

Abstract

In this article, numerical simulations of the electrical current-voltage characteristics of an n-Si / p-Si homojunction solar cell and an n-ZnO / p-Si heterojunction solar cell are performed. In order to find the optimal structure of the solar cells, numerical modelling using SCAPS-1D (Solar Cell Capacitance Simulator One Dimension) is performed. We study the effect of both emitter and base thicknesses and doping on the cell output parameters which are open circuit voltage (Voc), short circuit current density (Jcc), form factor (FF) and conversion efficiency (n). A comparison between the homojunction and heterojunction structures is also made in order to find which one of the two structures has the better conversion efficiency. For the same optimal values of the input parameters, we found that the conversion efficiency of the n-ZnO / p-Si heterojunction (23.23%) is higher than that of the n-Si / p-Si homojunction (20.08%). Therefore, the presence of a transparent conductive oxide (TCO) such as an n-ZnO layer on p-type silicon can improve the conversion efficiency of the solar cell due to the anti- reflection effect of the TCO layer.