In-vacancies in Si-doped InN

Christian Rauch 1Floris Reurings 1Filip Tuomisto 1Tim Veal 2Chris F. McConville 2Hai Lu 3William J. Schaff 3Chad S. Gallinat 4Gregor Koblmueller 4James S. Speck 4

1. Helsinki University of Technology, Department of Applied Physics (TKK), POB 1100, Otakaari 1 M, Espoo 02015-TKK, Finland
2. University of Warwick, Department of Physics, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
3. Cornell University, Electrical and Computer Engineering, Ithaca, NY 14853-540, United States
4. University of California, Santa Barbara, CA 93106, United States

Abstract

Despite of remarkable improvements in crystal quality during the last years, as-grown InN still exhibits a strong n-type tendency and considerably high defect concentrations [1]. Concerning native defects, recent calculations [2] predict In-vacancies to be the most abundant defect type in n-type InN and possess the tendency for forming complexes with other intrinsic defects or impurities [3], which raises the question of their impact on the materials properties. In this contribution we present results obtained with positron annihilation spectroscopy in MBE-grown Si-doped InN with electron concentrations from 1 x 1018 cm-3 to 6.6 x 1020 cm-3. Temperature dependent Doppler Broadening measurements show In-vacancies in concentrations from 2 x 1016 cm-3 to 7 x 1017 cm-3 which increase with increasing electron concentration in the material. These values are remarkably higher than what can be estimated from theoretically predicted formation energies of In-vacancies in InN based on experimentally determined Fermi levels in the investigated samples [4]. Additionally, a strong inhomogeneity of the defect distribution with an increasing vacancy concentration towards the layer/substrate-interface can be observed. These results suggest that the formation energy of In-vacancies is locally reduced in the vicinity of extended defects, which are especially abundant in the interface area - possibly through the formation of defect complexes. From the observed threshold for the formation of In-vacancies, which is seen by a comparison with earlier results in He-irradiated InN [5], it can be deduced that in spite of their still relatively low absolute concentrations In-vacancies play an important role in reducing the electron mobility in the material.

[1] B. Monemar et al., Phys. Stat. Sol. B 244, 1759-1768 (2007)

[2] C. Stampfl et al., Phys. Rev. B 61, R7846-R7849 (2000)

[3] X. M. Duan et al., Phys. Rev. B 79, 035207 (2009)

[4] P. D. C. King et al., Phys. Rev. B 77, 045316 (2008)

[5] F. Tuomisto et al., Phys. Rev. B 75, 193201 (2007)

Legal notice
  • Legal notice:

    Copyright (c) Pielaszek Research, all rights reserved.
    The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
    In every case, proper references including Author(s) name(s) and URL of this webpage: http://science24.com/paper/18432 must be provided.

 

Related papers
  1. Progress in the MBE Growth of InN
  2. Optical anisotropy of a- and m-plane InN grown on free-standing GaN substrates
  3. Could positrons be used to study interface properties in nitride devices?
  4. Irradiation-induced defects in InN and GaN studied with positron annihilation
  5. Surface and bulk electronic properties of significantly cation-anion mismatched oxide semiconductors
  6. Interface, bulk and surface electronic properties of InN
  7. Time-resolved differential transmission and photoluminescence studies of recombination mechanisms in Mg-doped InN 
  8. Electrical and optical properties of Mg-doped InN
  9. Recent Performance of Nonpolar/Semipolar/Polar GaN-based Blue LEDs/LDs and Bulk GaN Crystal Growth
  10. Pulsed positron beam for atomic and nanoscale characterization of thin films
  11. Ammonothermal Growth of Bulk GaN for Extended Time
  12. Compositional modulation in the InxGa1-xN layers; relation to their optical properties
  13. Recombination processes with and without momentum conservation in degenerate InN
  14. Characterization of chrystallographic properties and defects via X-ray microdiffraction in GaN(0001) layers
  15. Conduction band anisotropy of InN and GaN studied by synchrotron ellipsometry
  16. Surface band bending at n-type and p-type InN by Auger Electron Spectroscopy
  17. Acceptor states in photluminescence of n-InN
  18. Band Structure and Properties of InN and In-rich In1-xGaxN Alloys
  19. Quantized Electron Accumulation, Inversion Layers and Fermi Level-Stabilization in Indium Nitride
  20. Valence band structure of InN from x-ray photoemission studies
  21. InN explained within chemical trends
  22. Identification and recovery of electron irradiation induced point defects in ZnO
  23. Resonant tunneling and intersubband absorption in AlN-GaN-superlattices

Presentation: Oral at E-MRS Fall Meeting 2009, Symposium A, by Christian Rauch
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-05-11 15:53
Revised:   2009-06-07 00:48
Google
 
Web science24.com
© 1998-2021 pielaszek research, all rights reserved Powered by the Conference Engine