Evidence for enhanced carrier escape from multiple stepped quantum well (MSQW) and its impact on photovoltaic performance

Conference: IPRM 2011 - 23th International Conference on Indium Phosphide and Related Materials
05/22/2011 - 05/26/2011 at Berlin, Germany

Proceedings: IPRM 2011

Pages: 3Language: englishTyp: PDF

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Wen, Yu; Wang, Yunpeng; Nakano, Yoshiaki (Research Center for Advanced Science and Technology, the University of Tokyo, 4-6-1 Komaba, Meguro-Ku, Tokyo 153-8904, Japan)
Sugiyama, Masakazu (Department of Electrical Engineering and Information Systems, the University of Tokyo, Japan)

A multiple stepped quantum wells (MSQWs) solar cell, in which GaAs stepped-potential layers are sandwiched between strain-balanced InGaAs wells and GaAsP barriers, has been proposed. The bias-dependent photoluminescence has been studied to estimate the radiative recombination velocity, in comparison between the MSQW and the normal multiple quantum well (MQW) structures. Thermalized energy distribution from the wells was examined in terms of temperaturedependent PL and higher average carrier temperature was observed for MSQWs than for MQWs. Such enhanced carrier escape in the case of MSQWs allowed us to obtain increased short-circuit current density 25 mA/cm2 which is approximately 14% higher than that of a normal MQWs solar cell.