Deep levels in GaInNAs grown by molecular beam epitaxy and their concentration reduction with annealing treatment

Abstract

Deep-level transient Fourier spectroscopy (DLTFS) technique is used to investigate the thermal-annealing behaviour of at least five deep levels in two samples of Ga 0.987In 0.013N 0.0043As 0.9957, one medium doped with Si (2 × 10 16 cm −3) and the second one heavily doped with Si (1 × 10 18 cm −3) grown by molecular beam epitaxy (MBE). The thermal-annealing study was done at 650, 700, 750 and 800 °C for 5 min. One main electron trap with activation energy of 0.97 eV, a capture cross section of 5.5 × 10 −11 cm 2 and a density of 3.2 × 10 14 cm −3 is detected for the medium-doped as-grown sample. For the heavily doped sample one main electron trap with activation energy of 0.35 eV, a capture cross section of 7.1 × 10 −14 cm 2 and a density of 2.2 × 10 15 cm −3 is detected. For the heavily doped sample, this electron trap only decreases its density as the annealing temperature increases. No more deep centres appear with annealing. For the medium-doped sample, the main electron trap decreases its density as the annealing temperature increases, but unlike the heavily doped sample, four more deep centres appear, depending on the annealing temperature. Their annealing temperature dependence and possible origin of the electron traps are reported for the first time.