Analytical modelling of diffusion capacitance under monochromatic illumination: Static case

This study proposes an analytical modelling of the diffusion capacitance of a vertical-junction solar cell under monochromatic illumination in the static regime. The developed model incorporates the effects of illumination wavelength, base depth, and applied voltage, enabling an accurate description of the minority carrier dynamics within the junction. The results show that the diffusion capacitance decreases with increasing photon penetration depth and exhibits a nonlinear dependence on voltage. This analytical approach provides an efficient tool for predicting capacitive performance and may guide the optimization of solar cells in specialized photovoltaic applications.