Electrical, optical, and structural properties of GaN films prepared by hydride vapor phase epitaxy

A. Y. Polyakov, N. B. Smirnov, E. B. Yakimov, A. S. Usikov, H. Helava, K. D. Shcherbachev, A. V. Govorkov, Yu N. Makarov, In-Hwan Lee

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Two sets of undoped GaN films with the thickness of 10-20 μm were prepared by hydride vapor phase epitaxy (HVPE) and characterized by capacitance-voltage (C-V) profiling, microcathodoluminescence (MCL) spectra measurements, MCL imaging, electron beam induced current (EBIC) imaging, EBIC dependence on accelerating voltage, deep levels transient spectroscopy, high resolution X-ray diffraction measurements. The difference in growth conditions was mainly related to the lower (850 °C, group 1) or higher (950 °C, group 2) growth temperature. Both groups of samples showed similar crystalline quality with the dislocation density close to 10 8 cm -2 , but very different electrical and optical properties. In group 1 samples the residual donors concentration was ∼10 17 cm -3 or higher, the MCL spectra were dominated by the band-edge luminescence, and the diffusion length of charge carriers was close to 0.1 μm. Group 2 samples had a 2-4.5 μm thick highly resistive layer on top, for which MCL spectra were determined by green, yellow and red defect bands, and the diffusion length was 1.5 times higher than in group 1. We also present brief results of growth at the "standard" HVPE growth temperature of 1050 °C that show the presence of a minimum in the net donor concentration and deep traps density as a function of the growth temperature. Possible reasons for the observed results are discussed in terms of the electrical compensation of residual donors by deep traps.

Original languageEnglish
Pages (from-to)200-206
Number of pages7
JournalJournal of Alloys and Compounds
Volume617
DOIs
Publication statusPublished - 2014 Dec 25
Externally publishedYes

Keywords

  • Deep traps
  • Electrical compensation
  • GaN
  • Hydride vapor phase epitaxy
  • Residual donors

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Electrical, optical, and structural properties of GaN films prepared by hydride vapor phase epitaxy'. Together they form a unique fingerprint.

  • Cite this

    Polyakov, A. Y., Smirnov, N. B., Yakimov, E. B., Usikov, A. S., Helava, H., Shcherbachev, K. D., Govorkov, A. V., Makarov, Y. N., & Lee, I-H. (2014). Electrical, optical, and structural properties of GaN films prepared by hydride vapor phase epitaxy. Journal of Alloys and Compounds, 617, 200-206. https://doi.org/10.1016/j.jallcom.2014.07.208