Investigation of Cu(In, Ga)Se2 solar cell performance with non-cadmium buffer layer using TCAD-SILVACO

Abstract

The purpose of this work is to achieve the best efficiency of Cu(In, Ga)Se2 solar cells by replacing the CdS buffer layer with other nontoxic materials. The simulation tool used in this study is Silvaco-Atlas package based on digital resolution 2D transport equations governing the conduction mechanisms in semiconductor devices. The J-V characteristics are simulated under AM1.5G illumination. Firstly, we will report the modeling and simulation results of CdS/CIGS solar cell, in comparison with the previously reported experimental results [1]. Secondly, the photovoltaic parameters will be calculated with CdS buffer layer and without any buffer layer to understand its impact on the output parameters of solar cells. The simulation is carried out with the use of electrical and optical parameters chosen judiciously for different buffers (CdS, ZnOS and ZnSe). In comparison to simulated CdS/CIGS, the best photovoltaic parameters have been obtained with ZnOS buffer layer. The structure has almost the same open circuit voltage Voc and fill factor FF, and higher short circuit current density Jsc, which results in slightly higher conversion efficiencies.

Theoretical Investigation on Performance Enhancement of CIGS Based Solar Cells

“…where Ѱ(x) is the electrostatic potential, e is the electric charge,  0 and  r are vacuum and relative permittivities, p and n are the concentrations of holes and electrons, ND and NA are the donor and acceptor densities, p and n are the distributions of holes and electrons, Jn and Jp are the electron and hole densities, G(x) and R(x) are the generation and recombination rates, respectively. The simulation work for the two designed cells has been done by fitting the standard physical parameters of the materials collected from previously published papers [6,9,10]. All the input parameters are listed in Table 1.…”

“…But it has some limitations due to the presence of toxic Cd material in the CdS buffer layer. However, different non-cadmium and non-toxic materials such as ZnS, Zn(O, OH) and In2S3 were used as a buffer layer and investigated [6,7]. The aim of this work is to improve the efficiency of the solar cell by replacing the CdS layer with a wider-gap ZnSe layer.…”