Structure of the acceptor defects in P-type GaAsN grown by chemical beam epitaxy

The N-H related acceptor defects in p-type GaAsN grown by chemical beam epitaxy are studied by deep level transient spectroscopy (DLTS). Two new signals appear in DLTS spectra at 0.15 and 0.23 eV, when the crystals are grown using deuterated As source (D-TDMAAs). This indicates that the new peaks are originated from N-D related defects. There are two energy levels at 0.11 and 0.19 eV, which are considered to play the role of a double acceptor. The energy difference between 0.15 and 0.11 eV, and that between 0.23 and 0.19 eV are almost same, about 0.04 eV. Although these energy levels become deeper with increasing the growth temperature, the energy differences are almost constant independent of the growth condition. The intensity ratios of the peaks at 0.15 (0.23) eV to that at 0.11 (0.19) eV have a good correlation with the ratio of deuterium amount to that of hydrogen in the grown film. We conclude that the energy shifts occur due to the structural change from N-H to N-D in the same type of defect, and that this acceptor corresponds to N-H related defect.