Deep levels in Ga-doped ZnSe grown by molecular-beam epitaxy

Abstract

Deep levels in Ga-doped ZnSe films grown by molecular-beam epitaxy have been investigated through deep-level transient spectroscopy. Au/Ga-doped ZnSe Schottky diodes have two well-defined electron traps with activation energies of 0.26 eV (trap A), and 0.40–0.56 eV (trap B). The activation energy of trap B depends on the free-carrier concentration. The trap concentration in trap A and B is linearly proportional to the free-carrier concentration. The trap concentration, normalized by the free-carrier concentration, increases as the VI/II (Se/Zn) ratio increases. From these observations, we conclude that traps A and B can be ascribed to the complex of either the Zn vacancy and Ga or the interstitial Se and Ga.