Characteristics and parameters extracting of sub cells in dual-junction solar cells via capacitance-voltage measurement

Capacitance-voltage (C-V) have been mainly performed on single diode, have not yet been fully implemented for measuring multijunction (MJ) solar cells because a signal composed by different contributions of each subcell which are not easy to determine. We demonstrate how, using C-V technique, the parameters of each sub-cell through Dual Junction (DJ) solar cells can be determined. In this work, we propose a new approach using simple model and C-V method to characterize and evaluate the properties of the subcells in a monolithic DJ stack by extracting the important values of physical parameters, specifically the doping level (N) and the built-in voltage Vbi. To reach this goal, first we have measured the C-V characteristic of global dual-Junction GaAs/Ge solar cells. After, we have used Matlab software as success fully sound way to reach the behaviour of every single subcell.