Deep-level defects in MBE-grown Ga(As,N) layers

Abstract

Deep levels are examined in the whole band gap of strained Ga(As,N) with 3% GaN composition by deep-level transient Fourier spectroscopy on as-grown as well as annealed GaAs/Ga(As,N)/GaAs heterojunctions grown by molecular beam epitaxy. In the lower half of the band gap, there are only hole traps, which are not associated with nitrogen-related defects. For n-type structures, we find in as-grown samples a huge concentration of an electron trap at E C−0.25 eV, which is most likely connected with the nitrogen split interstitial defect (N–N) As. The concentration of this giant trap can be strongly reduced by rapid thermal annealing.