Reverse-bias screening of large-area GaAs/Ge solar cells at low and high temperatures

This paper presents the results of a series of reverse-bias tests performed by Lockheed Missiles and Space Company (LMSC). The purpose of the tests was twofold: to investigate the reverse-bias behavior of large-area (~4 cm×4.5 cm) gallium arsenide on germanium (GaAs/Ge) solar cells over a broad temperature regime, and to determine the most severe operating conditions within this regime in order to develop an effective production screening test. The tests were conducted in two phases. The first consisted of high-temperature (+93°C) reverse-bias screens and a high-temperature (+93°C) soak and cycling. The second set of tests included comparative reverse-bias screening at high (+93°C), low (-80°C), and room temperature, and a low-temperature reverse-bias soak. Dark I-V curves were taken at all three temperatures. The results of these tests show that the high-temperature test identifies susceptible cells more readily than the lower-temperature tests, though yields were close to 100% in all cases. The results confer a high level of confidence in the large-area GaAs/Ge cell to meet reverse-bias criteria for missions with stringent temperature and performance requirements