Defects in nitride-based semiconductors probed by positron annihilation

13th International Workshop on Slow Positron Beam Techniques and Applications

Uedono, A.^1 ; Sumiya, M.^2 ; Ishibashi, S.^3 ; Oshima, N.^4 ; Suzuki, R.^4

Division of Applied Physics, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan^1

Wide Bandgap Material Group, National Institute for Materials Science, Tsukuba Ibaraki 305-0044, Japan^2

Nanosystem Research Institute (NRI) RICS, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki 305-8568, Tsukuba, Japan^3

Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology, Ibaraki, 305-8568, Tsukuba, Japan^4

关键词: Annihilation radiations;    Coincidence doppler broadening;    Doppler broadening spectra;    Momentum distributions;    Monoenergetic positron beam;    Positron diffusion;    Projector augmented waves;    Vacancy-type defects;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/505/1/012009/pdf
DOI  :  10.1088/1742-6596/505/1/012009

来源: IOP

【 摘 要 】

Point defects in InxGa1-xN grown by metal organic chemical vapor deposition were studied by a monoenergetic positron beam. Measurements of Doppler broadening spectra of the annihilation radiation as a function of incident positron energy for InxGa1-xN (x 0.08 and 0.14) showed that vacancy-type defects were introduced with increasing InN composition. From comparisons between coincidence Doppler broadening spectra and the results calculated using the projector augmented-wave method, the major defect species was identified as the complexes between a cation vacancy and nitride vacancies. The concentration of the defects was found to be suppressed by Mg doping. An effect of Mg-doping on the positron diffusion properties in GaN and InN was also discussed. The momentum distribution of electrons at the InxGa1-xN/GaN interface was close to that in defect-free GaN or InxGa1-xN, which was attributed to the localization of positrons at the interface due to the electric field caused by polarizations.