Multiphonon capture of charge carriers by deep-level centers in a depletion region of a semiconductor

Abstract

Multiphonon field-assisted thermal capture of thermally equilibrium charge carriers by deep-level centers located in a depletion region of a semiconductor is analyzed. It is shown that, in the case of strong electron-phonon coupling (SEPC), the multiphonon capture with preliminary tunneling of an electron through a potential barrier in the depletion region occurs with a lower rate as compared to the direct multiphonon capture in the electrically neutral bulk of the semiconductor, whereas, in the case of weak electron-phonon coupling (WEPC), the capture rate in the depletion region of a semiconductor may exceed that in the electrically neutral bulk by several orders of magnitude. The results of experimental study of capture processes in AlGaAs doped with silicon indicate that electron-phonon coupling is strong in DX centers.