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Title: Growth and properties of Mg-doped In-polar InN films

Abstract

Mg doping into In-polar InN layers for different Mg fluxes is performed on GaN templates by molecular beam epitaxy, and their electrical and optical properties are investigated. Mg concentration is linearly proportional to Mg-beam flux, indicating that the Mg-sticking coefficient is almost unity. With Mg doping, electron concentration decreases by the effect of carrier compensation, but it begins to increase with further increasing Mg flux because of Mg-related donorlike-defects formation. For the partially carrier-compensated Mg-doped InN, two photoluminescence peaks are observed; one is originated from free-to-acceptor emission with an acceptor activation energy of about 61 meV and the other is similar to the conventional band-to-band emission.

Authors:
; ; ;  [1];  [2]
  1. Department of Electronics and Mechanical Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan)
  2. (Japan) and InN-Project as a CREST Program of JST, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan)
Publication Date:
OSTI Identifier:
20971928
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 90; Journal Issue: 20; Other Information: DOI: 10.1063/1.2741124; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ACTIVATION ENERGY; CRYSTAL GROWTH; DOPED MATERIALS; ELECTRON DENSITY; ELECTRONS; FILMS; GALLIUM NITRIDES; INDIUM NITRIDES; LAYERS; MAGNESIUM; MOLECULAR BEAM EPITAXY; OPTICAL PROPERTIES; PHOTOLUMINESCENCE; SEMICONDUCTOR MATERIALS

Citation Formats

Wang Xinqiang, Che, Song-Bek, Ishitani, Yoshihiro, Yoshikawa, Akihiko, and Venture Business Laboratory, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522. Growth and properties of Mg-doped In-polar InN films. United States: N. p., 2007. Web. doi:10.1063/1.2741124.
Wang Xinqiang, Che, Song-Bek, Ishitani, Yoshihiro, Yoshikawa, Akihiko, & Venture Business Laboratory, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522. Growth and properties of Mg-doped In-polar InN films. United States. doi:10.1063/1.2741124.
Wang Xinqiang, Che, Song-Bek, Ishitani, Yoshihiro, Yoshikawa, Akihiko, and Venture Business Laboratory, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522. Mon . "Growth and properties of Mg-doped In-polar InN films". United States. doi:10.1063/1.2741124.
@article{osti_20971928,
title = {Growth and properties of Mg-doped In-polar InN films},
author = {Wang Xinqiang and Che, Song-Bek and Ishitani, Yoshihiro and Yoshikawa, Akihiko and Venture Business Laboratory, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522},
abstractNote = {Mg doping into In-polar InN layers for different Mg fluxes is performed on GaN templates by molecular beam epitaxy, and their electrical and optical properties are investigated. Mg concentration is linearly proportional to Mg-beam flux, indicating that the Mg-sticking coefficient is almost unity. With Mg doping, electron concentration decreases by the effect of carrier compensation, but it begins to increase with further increasing Mg flux because of Mg-related donorlike-defects formation. For the partially carrier-compensated Mg-doped InN, two photoluminescence peaks are observed; one is originated from free-to-acceptor emission with an acceptor activation energy of about 61 meV and the other is similar to the conventional band-to-band emission.},
doi = {10.1063/1.2741124},
journal = {Applied Physics Letters},
number = 20,
volume = 90,
place = {United States},
year = {Mon May 14 00:00:00 EDT 2007},
month = {Mon May 14 00:00:00 EDT 2007}
}
  • Mg-doped InN films grown by plasma-assisted molecular beam epitaxy were characterized by infrared reflectance. Signatures of p-type conductivity in the spectra were obtained in the same doping density range where the existence of net acceptors was found by electrolyte capacitance-voltage measurements. Numerical spectrum analysis, which takes into account the large broadening factor of the normal mode energies of longitudinal optical phonon-plasmon coupling yielded high hole densities in the range of (0.1-1.2)x10{sup 19} cm{sup -3} and optical mobilities in the range of 25-70 cm{sup 2}/V s.
  • To investigate the Mg-dopability in In-polar InN epilayers grown by molecular beam epitaxy, polarity inversion dependence on Mg-doping level is studied. A multiple-InN layer-structure sample with different Mg-doping levels is grown and analyzed by transmission electron microscopy. Formation of high density V-shaped inversion domains is observed for the Mg-doped InN with Mg concentration ([Mg]) of 2.9x10{sup 19} cm{sup -3}. These domains lead to polarity inversion from In to N polarity. Further study for Mg-doped InN epilayers shows that polarity inversion takes place when [Mg] increases above 1.6x10{sup 19} cm{sup -3}. It is also shown that the Mg-sticking coefficient is almostmore » independent of the polarity.« less
  • The authors report on the plasma-assisted molecular beam epitaxy growth and carrier transport of Mg-doped In-face (0001) InN. The 1.2 {mu}m thick InN films were grown on GaN:Fe templates under metal rich conditions with Mg concentration from 1 Multiplication-Sign 10{sup 17}/cm{sup 3} to 3 Multiplication-Sign 10{sup 20}/cm{sup 3}. A morphological transition, associated with the formation of V-shape polarity inversion domains, was observed at Mg concentration over 7 Multiplication-Sign 10{sup 19}/cm{sup 3} by atomic force microscopy and transmission electron microscopy. Seebeck measurements indicated p-type conductivity for Mg-concentrations from 9 Multiplication-Sign 10{sup 17}/cm{sup 3} to 7 Multiplication-Sign 10{sup 19}/cm{sup 3}, i.e., asmore » it exceeded the compensating (unintentional) donor concentration.« less
  • In this work, photoluminescence (PL) properties of nearly defect-free Mg-doped InN nanowires were investigated in detail. The low-doped sample exhibits two PL emission peaks up to 152 K, which can be ascribed to the band-to-band recombination and the Mg-acceptor energy level related recombination, respectively. For the high-doped sample, the Mg-acceptor energy level related transition dominates. Detailed power dependent PL studies further indicate that the Mg-acceptor energy level related PL emission is due to the donor-acceptor pair recombination process, which subsequently evolves into the free-to-acceptor recombination with increasing temperature.
  • 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 × 10{sup 18} cm{sup −3} to 3.9 × 10{sup 21} cm{sup −3}. 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 × 10{sup 18} cm{sup −3} ≲ [Mg] ≲ 9.0 × 10{sup 19} cm{supmore » −3}. 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.« less