Title :
The potential for strain-balanced quantum well solar cells in terrestrial concentrator applications
Author :
Tibbits, T.N.D. ; Ballard, I.M. ; Barnham, K.W.J. ; Bushnell, D.B. ; Ekins-Daukes, N.J. ; Airey, R. ; Hill, G. ; Roberts, S.
Author_Institution :
Dept. of Exp. Solid State Phys., Blackett Lab., London, UK
Abstract :
Presently, monolithic tandem cells based on the Ga/sub 0.5/InP/GaAs material system are current limited by the lower GaAs junction. The effect of incorporating strain-balanced multi-quantum wells (MQW) into the lower junction is investigated, and efficiency enhancements under a range of spectra (AM1d to AM2.5d) are predicted. Although the open circuit voltage of an MQW cell may not be comparable to that of a GaAs cell, the additional current gain from improved current matching offsets the reduction in voltage, leading to an overall efficiency improvement in a tandem. Efficiency improvements of up to 4% absolute may be possible under AM1.5d 800x. MQW tandem cells will also benefit from light trapping schemes and active Ge substrates.
Keywords :
III-V semiconductors; dark conductivity; gallium arsenide; gallium compounds; indium compounds; quantum well devices; solar cells; solar energy concentrators; Ga/sub 0.5/InP/GaAs material system; GaAs junction; GaInP-GaAs; active Ge substrate; current gain; current matching offset; light trapping; monolithic tandem cell efficiency; open circuit voltage; strain balanced multiquantum well solar cell; terrestrial concentrator applications; voltage reduction;
Conference_Titel :
Photovoltaic Energy Conversion, 2003. Proceedings of 3rd World Conference on
Conference_Location :
Osaka, Japan
Print_ISBN :
4-9901816-0-3
