Raman Study of Defects in SI-GaAs and Se-doped Epitaxial Layer Irradiated by 10 MeV Electrons

摘要

Raman scattering measurements on Se-doped GaAs epitaxial layers and semi-insulating (SI) GaAs irradiated by 10 MeV electrons have been investigated. Several defect-related features were observed. We suggest that the 220 cm~(-1) mode is attribute to As_1 which is associated, at least in part, with EL2 and EL12 defects. For Se-doped samples, the Raman peaks at 205 and 258 cm~(-1) may be due to vibrational modes in small clusters of arsenic, and the 77,and 185 cm~(-1) modes are probably associated with disorder-activated first-order Raman scattering. Irradiated results show that the small clusters of arsenic and disorder state are increased with increasing irradiation fluences. Other Raman peaks will also be discussed in this paper.