Quality control method for a ZnSe single crystal by the dependence of the exciton two-photon luminescence power on the power of the exciting radiation

Abstract

The dependencies of the average exciton luminescence power in ZnSe and ZnSe crystal samples doped with Fe 2+ on the average excitation radiation (ER) power during two-photon absorption of this radiation in the samples were investigated. The experimental dependence of the average luminescence power as a function of the average ER power at each point of this functional dependence was approximated by a power function. The index of power for the ZnSe:Fe 2 + sample was close to 4 over the entire range of ER power, while in the ZnSe crystal without doping this the index of power depended on the ER power and decreased from 4.5 to 2.2 with increasing ER power. The obtained results are explained by the fact that the value of the index of power depends on the density of energy levels in the band gap associated with impuritydefect centers (IDC) in the samples, and the difference in the behavior of the index of power with the different power of ER in them is explained by a higher concentration of IDC in sample doped with iron compared to undoped. The simulation to support this point of view are provided. The results point to the possibility of assessing the quality of semiconductor crystals in terms of IDC density by the dependence of exciton twophoton luminescence power on the power of the ER upon its two-photon absorption.