Point defects in undoped semi-insulating GaAs: correlation between thermally stimulated current and positron annihilation spectroscopies

Abstract

Point defects and the main electron traps in undoped semi-insulating GaAs grown by vertical gradient freeze and high- and low-pressure liquid encapsulated Czochralski techniques have been studied by positron annihilation (PAS) and thermally stimulated current (TSC) spectroscopies, respectively. We find good correlations between the concentrations of the TSC traps T/sub 2/ (0.63 eV) and T/sub 5/ (0.35 eV), and the PAS identified-defects As/sub Ga/ and V/sub As/, respectively. A good correlation between the concentration of intrinsic acceptors (V/sub Ga/ and Ga/sub As/) measured by PAS, and the total acceptor concentration measured by infrared absorption, is also found.