Electric-field-enhanced electron emission from the EL5 deep-level defect in GaAs

Double-correlation deep-level transient spectroscopy has been used to study the electric-field-induced thermal emission of electrons from the EL5 defect in n-type GaAs crystal. Strongly anisotropic electric-field enhancement of this emission, which was the largest for the electric field parallel to the 〈1 0 0〉 crystallographic direction and the smallest for the 〈1 1 1〉 configuration, points to the trigonal symmetry of the defect potential and a strong coupling of the defect to the lattice vibronic modes. In view of the revealed results it is argued that a close pair divacancy complex can be responsible for the EL5 defect.