Title :
Dark-current suppression due to photon recycling in distributed Bragg reflector strain-balanced quantum well solar cells
Author :
Johnson, D.C. ; Ballard, I.M. ; Barnham, K.W.J. ; Bessiere, A. ; Bushnell, D.B. ; Connolly, J.P. ; Roberts, J.S. ; Hill, G. ; Calder, C.
Author_Institution :
Blackett Laboratory, Imperial Coll., London, UK
Abstract :
Self-absorption or photon recycling (PR) has been observed experimentally as a reduction in the ideality n=1 reverse saturation current of SB-QWSCs. We believe this is the first example of PR effects on solar cell dark-currents. PR is observed at high bias when the primary recombination mechanism in SB-QWSCs is radiative recombination in the quantum wells corresponding to ideality n=1 dark-currents. Results are presented here on the effect of PR on the dark-current and electroluminescence (EL) spectrum; PR has resulted in DBR SB-QWSC dark-current and EL suppression of up to 35% both experimentally and theoretically. Comparison is made to control cells without a DBR. Modelling results will allow us to make predictions for expected efficiency enhancement in optimised SB-QWSC devices at high concentration levels. These results convincingly reveal how PR can increase the efficiency of SB-QWSCs.
Keywords :
dark conductivity; electroluminescence; electron-hole recombination; quantum well devices; semiconductor device models; semiconductor quantum wells; solar cells; concentration levels; dark-current suppression; distributed Bragg reflector; efficiency enhancement; electroluminescence; photon recycling; radiative recombination; recombination mechanism; reverse saturation current; self-absorption; strain-balanced quantum well solar cells; Density estimation robust algorithm; Distributed Bragg reflectors; Gallium arsenide; Mirrors; Photovoltaic cells; Predictive models; Radiative recombination; Recycling; Reflectivity; Spontaneous emission;
Conference_Titel :
Photovoltaic Specialists Conference, 2005. Conference Record of the Thirty-first IEEE
Print_ISBN :
0-7803-8707-4
DOI :
10.1109/PVSC.2005.1488227
