Shunt diode analysis using light emission for gallium arsenide solar cell predictability

The use of light emission as a defect analysis technique has been expanded to better differentiate the types of shunt defects and analyze their effects on GaAs solar cells. Light emission from full-size 2 cm*2 cm space solar cells was detected, recorded, digitized and enhanced in order to analyze the low-level light emission and the shunt diode´s effects. Shunt diodes are of particular importance because they have been found to be the type of defect which is most likely to degrade and cause failure in GaAs solar cells. To analyze how the shunt diodes affect the quality of the solar cell, the pattern of light emission must be studied. In studying the low-level light emission, it was found that the pattern of light emission is different than that of the high-level light emission. The different light patterns show the changing effects of the shunt diodes. It is concluded that the shunt diode dominates over the junction diode at low values of current and that the junction diode dominates over the shunt diode at high values of current.