Intracenter transitions in the dominant deep level (EL2) in GaAs

Abstract

Intracenter transitions in the major deep level EL2 in GaAs were identified for the first time by superimposing photocurrent measurements on those of optical absorption. These transitions were found to be responsible for the characteristic EL2 absorption band between 1.0 and 1.3 eV. At low temperatures (<60 K) intracenter absorption exhibits a fine structure involving the zero phonon line and replicas at energies close to those of transverse acoustic phonons (TA). This coupling with TA phonons is a strong indication that EL2 is an extrinsic self-trapping center.