GaAs-AlGaAs heterojunction solar cells with increased open-circuit voltage

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:191160

Ragay, F W; Ruigrok, E W.M.; Wolter, J H ^[1]

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1. Eindhoven Univ. of Technology (Netherlands)

In order to reduce the dark current, the authors studied the incorporation of AlGaAs layers at the junction of GaAs solar cells. According to Shockley`s diode model, the dark current is reduced in case the junction is made of wide bandgap material. However, the GaAs-AlGaAs interfaces form a potential barrier for the generated carriers, which degrades the collection efficiency and sets a limit to the Al concentration. A set of homojunction cells, GaAs and Al{sub 0.1}Ga{sub 0.9}As, and heterojunction cells, with Al concentration of 5, 10 and 15%, as well as a cell with quantum wells have been fabricated. For the characterization, the authors measured dark current, I-V curve under illumination, temperature dependence of the short-circuit current, spectral response and the emission spectra. Compared to the GaAs cell the heterojunction cells reveal a higher open-circuit voltage, due to the reduced dark current. The 5% heterojunction cell showed only a small degradation of the short-circuit current, and relative to the GaAs cell the efficiency was enhanced by 7%. In case of the MQW cell and the 10 and 15% heterojunction cells the reduction of the short-circuit current was more extreme and the advantage of the higher open-circuit voltage was by far compensated, resulting in a reduced efficiency compared to the GaAs cell.

• OSTI ID: 191160
• Report Number(s): CONF-941203--; ISBN 0-7803-1459-X
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
GALLIUM ARSENIDES
HETEROJUNCTIONS
INTERFACES
PERFORMANCE
SOLAR CELLS