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High Temperature Growth for High Performance Selenization CIGS Solar Cells
T. Okato, R. Usui, T. Tomizawa, Y. Sera, H. Odaka
EBIC, CIGS, Thin Film Solar Cell, Interface(s), EDX, High Strain Point Glass
Thin Film Solar Cells
Subtopic: CdTe, CIS and Related Ternary and Quaternary Thin Film Solar Cells
Event: 27th European Photovoltaic Solar Energy Conference and Exhibition
Session: 3CO.2.2
2216 - 2218
ISBN: 3-936338-28-0
Paper DOI: 10.4229/27thEUPVSEC2012-3CO.2.2
0,00 EUR
Document(s): paper


High strain point glass is designed to tolerate much higher temperature than standard SLG. The use of the high strain point glass enables CIGS growth at high temperatures. The purpose of this work is to demonstrate the importance of the high temperature growth for the selenization CIGS solar cells. We show that by increasing the temperature beyond which SLG is difficult to use the cell efficiency can be improved, and we achieve our highest efficiency of 17.5%. Further increase of the temperature leads to efficiency decrease. We assume that Ga diffusion is the key to understand this behavior and employed simultaneous observation of EBIC and EDX. At lower temperature segregation of the Ga is found, which suggests more thermal energy is necessary to diffuse the Ga. Increasing the temperature to 580ÂșC, the Ga diffuses uniformly to create identical profile of the pn junction. Carrier density and life time measurements are also performed and we confirm the improved crystal quality thanks to the high temperature process. Further increase of the temperature, the Ga migrates throughout the CIGS layer resulting in the low efficiency.