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

fYear

1990

fDate

21-25 May 1990

Firstpage

68

Abstract

The development of a graded-emitter Al_0.8Ga_0.92As 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 Al_xGa_(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 V_oc and I_sc 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; Al_xGa_1-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;

fLanguage

English

Publisher

ieee

Conference_Titel

Photovoltaic Specialists Conference, 1990., Conference Record of the Twenty First IEEE

Conference_Location

Kissimmee, FL

Type

conf

DOI

10.1109/PVSC.1990.111593

Filename

111593