Hydrogenated indium oxide window layers for high-efficiency Cu(In,Ga)Se-2 solar cells

作者：Jaeger Timo; Romanyuk Yaroslav E; Nishiwaki Shiro; Bissig Benjamin; Pianezzi Fabian; Fuchs Peter; Gretener Christina; Doebeli Max; Tiwari Ayodhya N

来源：Journal of Applied Physics, 2015, 117(20): 205301.

DOI：10.1063/1.4921445

High mobility hydrogenated indium oxide is investigated as a transparent contact for thin film Cu(In, Ga)Se-2 (CIGS) solar cells. Hydrogen doping of In2O3 thin films is achieved by injection of H2O water vapor or H-2 gas during the sputter process. As-deposited amorphous In2O3:H films exhibit a high electron mobility of similar to 50 cm(2)/Vs at room temperature. A bulk hydrogen concentration of similar to 4 at. % was measured for both optimized H2O and H-2-processed films, although the H2O-derived film exhibits a doping gradient as detected by elastic recoil detection analysis. Amorphous IOH films are implemented as front contacts in CIGS based solar cells, and their performance is compared with the reference ZnO:Al electrodes. The most significant feature of IOH containing devices is an enhanced open circuit voltage (V-OC) of similar to 20mV regardless of the doping approach, whereas the short circuit current and fill factor remain the same for the H2O case or slightly decrease for H-2. The overall power conversion efficiency is improved from 15.7% to 16.2% by substituting ZnO:Al with IOH (H2O) as front contacts. Finally, stability tests of non-encapsulated solar cells in dry air at 80 degrees C and constant illumination for 500 h demonstrate a higher stability for IOH-containing devices.

• 出版日期2015-5-28