GaAs/Ge and silicon solar cell capacitance measurement using triangular wave method

The capacitance of GaAs/Ge and silicon (BSFR) solar cells are measured at different temperature ranging from 288 to 338 K under dark condition using triangular wave method. It is a frequency domain technique. In the proposed method, the solar cells are biased externally using DC voltage at the desired operating voltage and the AC triangle wave small signal of desired amplitude with variable frequencies are applied. The resultant AC current of the device is measured and the cell capacitance is calculated. GaAs/Ge solar cell has shown only transition capacitance throughout its operating voltage while silicon (BSFR) solar cell exhibited both transition and diffusion capacitances. It is a direct and simple measurement technique in comparison to impedance spectroscopy and other bridge methods.