Improved photovoltaic and grain boundary characteristics of single elementary target-sputtered Cu2ZnSnSe4 thin films by post sulfurization/selenization process. (22nd May 2015)

• Record Type: Journal Article
• Authors: Jo, Yeon Hwa; Jang, Jin Woo; Mohanty, Bhaskar Chandra; Kang, Han Byul; Cho, Yong Soo
• Is Part Of: Journal of physics. Volume 48:Number 24(2015)
• Publication Date: 2015-05-22
• Subjects: Cu2ZnSnSe4 -- sputtering -- thin film solar cells -- grain boundary -- sulfurization; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/48/24/245103
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: A potential way to improve the quality of Cu2 ZnSnSe4 absorber thin film by a one step process of sputtering using a single elementary target is proposed for thin film solar cells. As critical parameters, different S/Se ratios and grain boundary characteristics are achieved by adjusting sequential sulfurization and selenization post-treatment. The simple sulfurization of as-deposited film at 530 °C in H2 S is not effective in raising the performance but the additional Se annealing at a shorter duration of 5 min improves conversion efficiency from 0.12 to 3.21% with a drastic increase of the open circuit voltage. Positively-charged grain boundaries with narrow potential peaks seem to play a critical role for effective exciton separation and higher efficiency. The improvement is also understood as related to well-defined microstructures and the variable optical band gap.