Deep-level defects, in p-type heterostructures which had been grown by molecular beam epitaxy, were investigated by using transient Fourier spectroscopy. Depth-resolved distributions of hole traps were measured, in as-grown and annealed heterojunctions, in order to identify the defects which led to the degradation of GaAsN properties. Four defects were detected in the heterostructures. Two predominant hole traps were found, in GaAsN, at energies of about 0.35 and 0.45eV above the valence-band edge. These mid-gap levels originated from Cu- and Fe-related defects. Both traps were removed by annealing, and were suggested to be non-radiative centres that degraded the optical properties. Two other hole traps of intrinsic origin were related to the GaAs growth conditions close to the GaAsN/GaAs interface. The GaAsN layers and GaAs/GaAsN interfaces were essentially defect-free after rapid thermal annealing.

Origin and Annealing of Deep-Level Defects in p-Type GaAs/Ga(As,N)/GaAs Heterostructures Grown by Molecular Beam Epitaxy. P.Krispin, S.G.Spruytte, J.S.Harris, K.H.Ploog: Journal of Applied Physics, 2001, 89[11], 6294-301