Evidence for atomic scale disorder in indium nitride from perturbed angular correlation spectroscopy

Abstract

The crystal lattice of bulk grains and state-of-the-art films of indium nitride was investigated at the atomic scale with perturbed angular correlation spectroscopy using the 111 In/Cd radioisotope probe. The probe was introduced during sample synthesis, by diffusion and by ion implantation. The mean quadrupole interaction frequency ν Q = 28 MHz was observed at the indium probe site in all types of indium nitride samples with broad frequency distributions. The observed small, but non-zero, asymmetry parameter indicates broken symmetry around the probe atoms. Results have been compared with theoretical calculations based on the point charge model. The consistency of the experimental results and their independence of the preparation technique suggest that the origin of the broad frequency distribution is inherent to indium nitride, indicating a high degree of disorder at the atomic scale. Due to the low dissociation temperature of indium nitride, furnace and rapid thermal annealing at atmospheric pressure reduce the lattice disorder only marginally.

Implanted Impurities in Wide Band Gap Semiconductors

“…At room temperature Dogra et al [22] observed a QIF of ν Q = 28 MHz at the cation site in InN which is consistent with measurements for other nitrides. However, it was not possible to anneal the implantation damage completely, which is attributed to inherent defects in the InN lattice.…”

Compositional and structural characterization of indium nitride using swift ions

“…The perturbed angular correlation spectroscopy of indium nitride carried out in this work utilizing the radioisotope 111 In/Cd led to the discovery of n ¼ 28 MHz as the interaction frequency for this probe [16,17]. This is consistent with measurements for gallium nitride (6 MHz) and aluminium nitride (32 MHz) and also with expectation due to the generally low electric field gradient of wurtzite lattices.…”

“…The bulk grains were doped during synthesis, whereas the probe was ion-implanted into RPECVD-and MBE-grown films after growth [16,17]. The 111 In/Cd radioisotope is particularly suited to the study of indium nitride since it can be expected that the atoms occupy indium lattice sites prior to the radioactive decay of their nucleus.…”

“…It cannot be fully excluded that the disorder is partly due to the ion implantation of the radioisotope probe. The fact that, despite the use of different doping techniques [16,17], such disorder has been observed for all indium nitride materials studied suggests, however, that as-grown films are already riddled with diverse defect structures.…”

The Potential of the Perturbed Angular Correlation Technique in Characterizing Semiconductors

“…These results revealed the formation of Pd-V and Pd-B defect complexes, respectively, in highly doped n-and p-Si. Figure 3d shows the PAC spectrum of polycrystalline synthesized InN, where the leastsquares fitted parameters reveal the presence of In 2 O 3 contents in the sample; 43 the starting materials for synthesis was In 2 O 3 . Besides, we observed an interaction frequency of 28 MHz having a broad distribution with a small nonzero value of asymmetry parameter at the indium site in an InN crystal lattice.…”