Effects of the Modified TCO Sputtering Condition on ZnS/CIGS Solar Cell

Abstract

The Cu(In,Ga)Se₂(CIGS) thin film solar cells were fabricated using ZnS buffer layer deposited by chemical bath deposition and ZnO/Al-doped ZnO transparent conducting layers deposited by magnetron sputtering with two different configurations of target-to-substrate angle and distance in order to evaluate the effect of plasma damage on device performance. The higher efficiency was obtained from the configuration of the substrate being far away from the target center than face-to-face configuration, suggesting that the excessive bombardment of high energy particles from the plasma on the film surface is responsible for the solar cell performance degradation. It is suggested that the improved open-circuit voltage is ascribed to the increased recombination barrier height.

Keywords:

• CIGS solar cell
• Cd-free buffer layer
• ZnS buffer
• plasma damage

Acknowledgments

This research was financially supported by the Ministry of Education, Science Technology (MEST) and national research foundation of Korea (NRF) through the Human Resource Training Project for Regional Innovation. The authors appreciate the financial support from “Development of 25% Efficiency Grade Tandem CIGS Thin Film Solar Cell Core Technology “ of MKE (Ministry of Knowledge Economy) and ISTK (Korea Research Council for Industrial Science and Technology) of Republic of Korea.