Distribution of built-in electrical potential in GaInP2/GaAs tandem-junction solar cells

Abstract
Distributions of built-in potential in GaInP2/GaAs tandem-junction solar cells were investigated by scanning Kelvin probe microscopy. Two states of potential distribution resulting from flattening of band bending and charge accumulation on either the top or bottom p–n junction were observed under short circuit, depending on the illumination spectra. With an external bias voltage, the voltage change always happened on the junction with the charge accumulation, and the potential distribution between the two states became less sensitive to illumination spectra.