Evidence for the electron traps at dislocations in GaAs crystals

Abstract

A new electron trap, labeled ED1, with an activation energy of 0.68 eV has been found to appear in the deep-level transient spectroscopy spectrum of n-type GaAs crystals as a result of their plastic deformation at 400 °C. The trap has been systematically investigated taking into account broadening of its energy level. The trap concentration was proportional to the dislocation density and not affected by the post-deformation annealing at 500 °C. The concentration of electrons captured at the trap was found to depend logarithmically on the duration time of the filling pulse and an acceptor character of the trap was established. The results are analyzed in a model involving barrier-limited capture rate, and it is concluded that the ED1 traps are most probably located in the dislocation core. Possible types of dislocations responsible for the traps are discussed.