Determination of a Dominat Photocarrier Type in Variously Doped Cd x Zn 1-x Te:V:As:Cl Crystals

A novel way to determine a type of dominant carriers photoexcited from deep traps in a photorefractive semiconductor is presented. Numerical analysis of a picosecond free-carrier grating dynamics in presence of SC field revealed an excitation intensity dependent grating diffusive decay time ?D ~ D -1, if the carriers partially screen the SC field in deep traps. An increase (decrease) of effective diffusion coefficient D with excitation intensity is a signature that electrons are the major (minor) carriers photoexcited from deep traps. The method has been verified in number of vanadium-doped and shallow impurity Cl and/or As co-doped CdZnTe bulk crystals.