Regular Article

Ultrathin CdTe solar cells with absorber layer thinner than 0.2 microns

¹ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, PR China
² Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, PR China

^* e-mail: eedewang@ustc.edu.cn

Received: 11 May 2018
Received in final form: 29 June 2018
Accepted: 17 July 2018
Published online: 18 October 2018

Abstract

In this study, ultrathin Cadmium telluride (CdTe) solar cells with absorber thickness from 50 to 200 nm were fabricated. The short-circuit current (J_SC) and open-circuit voltage (V_OC) were found to decrease significantly with the thickness of absorber layer decreasing. The decrease of the J_SC was mainly because of the insufficient light absorption. Even so, the J_SC was still found to be 8.2 mA/cm², which was about 32% of that of a normal CdTe solar cell when the thickness of absorber layer was reduced to ∼1% of that of a normal CdS/CdTe solar cell, i.e. 50 nm. The reasons, which caused the decrease of V_OC, were also discussed in this study. The dark current–voltage characteristics were analyzed and the contribution of ohmic shunting current to the total leakage current was found to increase with the thickness of CdTe absorber layer decreasing. The device characteristics of the ultrathin CdTe solar cells under weak light irradiance and at different temperatures were also investigated. This study provides a guideline for the fabrication of ultrathin CdTe solar cells in the future.