Deep levels in α-irradiated p-type MOCVD GaAs

Abstract

Irradiation of p-GaAs grown by low-pressure metal-organic chemical-vapor deposition (LP-MOCVD) with α-particles from the 241Am source has been performed at room temperature. At least seven radiation-induced deep-level defects at energy positions E v+0.09 eV, E v+0.11 eV, E v+0.16 eV, E v+0.24 eV, E v+0.32 eV, E v+0.42 eV, and E v+0.77 eV were detected in the lower-half of the band gap, using deep-level transient spectroscopy (DLTS), while no radiation-induced defects were observed in the upper-half band gap (minority carrier injection spectrum). The DLTS signatures of the radiation-induced defects are compared with the previously reported defects introduced in α-irradiated p-GaAs grown by molecular beam epitaxy (MBE). It has been observed that while four of these deep levels are similar to those found in α-irradiated MBE grown p-GaAs, three levels at E v+0.32 eV, E v+0.42 eV, and E v+0.77 eV observed in our MOCVD material were not detected in MBE material. Data on the introduction rates and other characteristics of the radiation-induced defects are presented.