The study of the influence of the surface and bulk parameters on the depletion region, created by electronic excitation, has been performed on p-type CdTe. The surface effect is given by two parameters: the energy of surface defects (Et) and their surface state density (Nt). However the volume effect is characterized by the diffusion length (Ln) and the concentration of acceptors (Na). This investigation demonstrated that, for high values of the excitation beam intensity, the depth of the depletion region (Z d ) decreases as Et and Nt decrease and when Na and Ln increase.