Title :
Graded-band-gap AlGaAs solar cells for AlGaAs/Ge cascade cells
Author :
Timmons, M. ; Venkatasubramanian, R. ; Colpitts, T. ; Hills, J. ; Hutchby, J. ; Iles, P. ; Chu, C.
Author_Institution :
Res. Triangle Inst., Research Triangle Park, NC, USA
Abstract :
The development of a graded-emitter Al0.8Ga0.92 As cell that is to be incorporated in an AlGaAs/Ge cascade cell and that has essentially equaled the performance predicted by initial modeling is described. The AlxGa(1-x)As is graded from x=0.08 to 0.18 in a 0.25 μm thick emitter. The best measured efficiency for the structure under AM0 conditions is 19.5% using an Al 2O3 single-layer antireflection coating. Optimization of the growth process using minority carrier properties has produced improved AlGaAs material quality and, therefore, better cells. Preliminary radiation resistance measurements suggest that AlGaAs cells retain greater fractions of Voc and Isc than GaAs cells when irradiated with 1 MeV electron fluences greater than 1015/cm2, and graded-emitter cells performed the best in the AlGaAs group, although the grading in the tested cells was not optimized
Keywords :
III-V semiconductors; aluminium compounds; elemental semiconductors; gallium arsenide; germanium; semiconductor growth; solar cells; 0.25 micron; 1 MeV; 19.5 percent; Al2O3; AlxGa1-xAs; AlGaAs-Ge; antireflection coating; cascade cells; development; emitter; graded bandgap; growth; minority carrier; performance; radiation resistance; solar cells; Cities and towns; Coatings; Electrical resistance measurement; Electrons; Inductors; Performance evaluation; Photovoltaic cells; Predictive models; Solar energy; Testing;
Conference_Titel :
Photovoltaic Specialists Conference, 1990., Conference Record of the Twenty First IEEE
Conference_Location :
Kissimmee, FL
DOI :
10.1109/PVSC.1990.111593
