Microscopic structure of DX centers in Cd 0.8Zn 0.2Te:Cl

Abstract

Photoexcitation of chlorine DX centers induces a transition of the Cl atoms to the shallow-donor state and persistent photoconductivity at low temperature in Cd 0.8Zn 0.2Te:Cl. The relaxation of the substitutional Cl atoms to the DX state at 140 K is coincident with a decrease of the positron line-shape parameter and an increase of annihilation with high-momentum core electrons. The results indicate positron trapping and annihilation at DX centers and at chlorine A centers. The data support the bond breaking model of the DX centers and the outward relaxation of the Cl and Cd(Zn) atoms alone the [111] direction. The thermal barrier for the shallow-deep transition was found to be 0.44 eV.link_to_subscribed_fulltex