A relationship between intra- 4f transitions of Er and vacancy-type defects in Er-doped GaN was studied by using a monoenergetic positron beam. Doppler broadening spectra of the annihilation radiation were measured for Er-doped GaN grown by molecular beam epitaxy. A clear correlation between the defect concentration and the photoluminescence (PL) intensity was observed. The major defect species detected by positrons was identified as a Ga vacancy VGa, and its concentration increased with increasing Er concentration [Er]. For the sample with [Er] =3.3 at. %, the maximum integrated intensity of PL was observed. The VGa concentration was above 1018 cm-3 and additional vacancies such as divacancies started to be introduced at this Er concentration. For the sample with higher [Er], the PL intensity decreased, and the mean size of vacancies decreased due to an introduction of precipitates and/or metastable phases. © 2008 American Institute of Physics.
CITATION STYLE
Uedono, A., Shaoqiang, C., Jongwon, S., Ito, K., Nakamori, H., Honda, N., … Ishibashi, S. (2008). Vacancy-type defects in Er-doped GaN studied by a monoenergetic positron beam. Journal of Applied Physics, 103(10). https://doi.org/10.1063/1.2932166
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