Vacancy-type defects in Mg-doped InN probed by means of positron annihilation

Uedono, Akira; Nakamori, H.; Narita, Keishi; Suzuki, Jinya; Wang, Xinqiang; Che, Song-Bek; Ishitani, Yoshihiro; Yoshikawa, Akihiko; Ishibashi, Shoji

doi:10.1063/1.3075907

Cited by 25 publications

(15 citation statements)

References 39 publications

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“…V In -mV N , in accordance to what has been proposed earlier in Mg-doped InN. 20 Based on the TEM data, the observed increase in vacancy clustering at the InN/Gan interface coincides with elevated dislocation densities in that area. In order to assess the effect of dislocations on the formation energies of point defects in their vicinity, we performed DFT calculations of strained InN lattices.…”

Section: à2supporting

confidence: 90%

Defect evolution and interplay in n-type InN

Rauch

Tuomisto

Vilalta‐Clemente

et al. 2012

Applied Physics Letters

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The nature and interplay of intrinsic point and extended defects in n-type Si-doped InN epilayers with free carrier concentrations up to 6.6 × 10 20 cm −3 are studied using positron annihilation spectroscopy and transmission electron microscopy and compared to results from undoped irradiated films. In as-grown Si-doped samples, VIn-VN complexes are the dominant III-sublattice related vacancy defects. Enhanced formation of larger VIn-mVN clusters is observed at the interface, which speaks for a high concentration of additional VN in the near-interface region and coincides with an increase of the dislocation density in that area.

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Section: à2supporting

confidence: 90%

Defect evolution and interplay in n-type InN

Rauch

Tuomisto

Vilalta‐Clemente

et al. 2012

Applied Physics Letters

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“…Similar behavior of the S values was also observed for In x Ga 1-x N, and this is typical for group-III nitride films grown by heteroepitaxial growth. 29,30,32 The observed SÀE curves were fitted using Eq. shown.…”

Section: Methodsmentioning

confidence: 99%

Vacancy-type defects in InxGa1–xN alloys probed using a monoenergetic positron beam

Uedono

Ishibashi

Watanabe

et al. 2012

Journal of Applied Physics

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Native defects in InxGa1–xN grown by plasma-assisted molecular beam epitaxy were probed by a monoenergetic positron beam. Doppler broadening spectra of the annihilation radiation were measured, and these were compared with results obtained using first-principles calculation. The defect concentration increased with increasing In composition x and reached the maximum at x = 0.44∼0.56. A clear correlation between the line-width of photoluminescence and the defect concentration was obtained. The major defect species detected by positron annihilation was identified as cation vacancies coupled with multiple nitrogen vacancies (VNs), and their introduction mechanism is discussed in terms of the strain energy due to bond-length/angle distortions and the suppression of the VN formation energy by neighboring In atoms.

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“…30,34 Positron annihilation studies of N-polar InN:Mg identified nitrogen vacancy clusters for Mg concentrations below 2 Â 10 19 cm À3 while for Mg concentrations above the p-type window (when the conductivity is switched to n-type again) complexes between indium vacancy and nitrogen vacancy clusters were found. 35 Recently, Choi et al 36 reported on the degradation of surface morphology and onset of polarity inversion for Mg concentration above 7 Â 10 19 cm À3 . It has also been found that zinc-blende (ZB) InN is formed when Mg concentration exceeds 1.8 Â 10 20 cm À3 (Ref.…”

Section: Introductionmentioning

confidence: 99%

Effect of Mg doping on the structural and free-charge carrier properties of InN films

Xie¹,

Sédrine²,

Schöche³

et al. 2014

Journal of Applied Physics

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We present a comprehensive study of free-charge carrier and structural properties of two sets of InN films grown by molecular beam epitaxy and systematically doped with Mg from 1.0 Â 10 18 cm À3 to 3.9 Â 10 21 cm À3 . The free electron and hole concentration, mobility, and plasmon broadening parameters are determined by infrared spectroscopic ellipsometry. The lattice parameters, microstructure, and surface morphology are determined by high-resolution X-ray diffraction and atomic force microscopy. Consistent results on the free-charge carrier type are found in the two sets of InN films and it is inferred that p-type conductivity could be achieved for 1.0 Â 10 18 cm À3 Շ [Mg] Շ 9.0 Â 10 19 cm À3 . The systematic change of free-charge carrier properties with Mg concentration is discussed in relation to the evolution of extended defect density and growth mode. A comparison between the structural characteristics and free electron concentrations in the films provides insights in the role of extended and point defects for the n-type conductivity in InN. It further allows to suggest pathways for achieving compensated InN material with relatively high electron mobility and low defect densities. The critical values of Mg concentration for which polarity inversion and formation of zinc-blende InN occurred are determined. Finally, the effect of Mg doping on the lattice parameters is established and different contributions to the strain in the films are discussed. V C 2014 AIP Publishing LLC.

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Vacancy-type defects in Mg-doped InN probed by means of positron annihilation

Cited by 25 publications

References 39 publications

Defect evolution and interplay in n-type InN

Defect evolution and interplay in n-type InN

Vacancy-type defects in InxGa1–xN alloys probed using a monoenergetic positron beam

Effect of Mg doping on the structural and free-charge carrier properties of InN films

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