Low temperature quantum efficiency measurements on irradiated multijunction solar cells

This paper presents quantum efficiency (QE) measurements and analyses on monolithic triple junction (3J) InGaP/GaAs/Ge solar cells under both room (300K) and low temperature (130K) conditions. In measuring the quantum efficiency of multijunction solar cells, one must be careful to use the proper bias conditions to isolate the subcell of interest. This may be achieved by using external light sources such as filtered lamps, lasers, or LEDs. In some instances, an additional electrical bias is necessary. The choice of bias is also dependent on the temperature and/or irradiation condition of the solar cell. This paper will describe these measurements in detail and provide some QE analyses on irradiated multijunction solar cells at low temperature.