Nonradiative Recombination at Dislocations in III-V Compound Semiconductors

Abstract

SUMMARY Carrier recombination at individual dislocations is investigated for the case of misfit dislocations at a heterojunction between Ga1–xAlxAs1–yPy epitaxial layers. Through the combined use of scanning transmission electron microscopy, electron beam induced current and cathodoluminescence analysis, it is shown that the non-radiative and radiative recombination properties of dislocations are associated with their fine crystallographic configuration. The edge Lomer-Cottrell dislocation is found to be electrically neutral. The absence of carrier recombination strongly suggests that core reconstruction may be important in eliminating dangling bonds and kink sites along the core of these dislocations. An undissociated dislocation with a Burgers vector b=1/2a〈110〉 is proposed as the more likely configuration for the edge Lomer-Cottrell dislocation. An asymmetry in the nonradiative recombination properties and crystallographic structure of the 60° dislocation is also reported and discussed.