Vacancy-type defects in Er-doped GaN studied by a monoenergetic positron beam
- Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan)
- Research Institute for Computational Sciences, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, 305-8568 (Japan)
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 V{sub Ga}, 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 V{sub Ga} concentration was above 10{sup 18} cm{sup -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.
- OSTI ID:
- 21137274
- Journal Information:
- Journal of Applied Physics, Vol. 103, Issue 10; Other Information: DOI: 10.1063/1.2932166; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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