Deep hole traps in p-type nitrogen-doped ZnSe grown by molecular beam epitaxy

Abstract

P-type nitrogen-doped ZnSe grown on n+-GaAs by molecular beam epitaxy has been studied by deep-level transient spectroscopy (DLTS) and double correlation DLTS. To achieve p-type doping of ZnSe, we employed an active nitrogen beam produced by a free-radical plasma source. Four hole traps—with activation energies of 0.22, 0.51, 0.63, and 0.70 eV—were detected by DLTS. Two of these—those at 0.51 and 0.63 eV—have never been observed before in ZnSe. They are probably introduced to the material by nitrogen doping. The properties of the other two traps—at 0.22 and 0.70 eV—support the hypothesis that both of them are associated with native defects, in agreement with earlier reports. To our knowledge this is the first report about direct experimental investigation of deep states in p-type ZnSe.