Properties of κ-Ga2O3 Prepared by Epitaxial Lateral Overgrowth

Alexander Polyakov, In Hwan Lee, Vladimir Nikolaev, Aleksei Pechnikov, Andrew Miakonkikh, Mikhail Scheglov, Eugene Yakimov, Andrei Chikiryaka, Anton Vasilev, Anastasia Kochkova, Ivan Shchemerov, Alexey Chernykh, Stephen Pearton

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The structural and electrical properties of undoped and Sn doped κ-Ga2O3 layers grown by epitaxial lateral overgrowth on TiO2/sapphire substrates using stripe and point masks show that the crystalline structure of the films can be greatly improved relative to conventional planar growth. The undoped films are semi-insulating, with the Fermi level pinned near EC-0.7 eV, and deep electron traps at EC-0.5 eV and EC-0.3 eV are detectable in thermally stimulated current and photoinduced current transient spectra measurements. Low concentration Sn doping results in net donor concentrations of ≈ 1013 cm−3, and deep trap spectra determined by electron traps at EC-0.5 eV, and deep acceptors with an optical ionization threshold near 2 and 3.1 eV. Treatment of the samples in hydrogen plasma at 330 °C increases the donor density near the surface to ≈ 1019 cm−3. Such samples show strong persistent photocapacitance and photoconductivity, indicating the possible DX-like character of the centers involved. For thin (5 µm) κ-Ga2O3 films grown on GaN/sapphire templates, p-type-like behavior is unexpectedly observed in electrical properties and we discuss the possible formation of a 2D hole gas at the κ-Ga2O3/GaN interface.

Original languageEnglish
JournalAdvanced Materials Interfaces
DOIs
Publication statusAccepted/In press - 2023

Bibliographical note

Funding Information:
The work at NUST MISiS was supported in part by a grant from the Ministry of Science and Higher Education of Russian Federation (Agreement # 075‐15‐2022‐1113). The authors gratefully acknowledge helpful discussions with Dr. S. Yu. Karpov of STR Soft‐Impact, S. Petersburg.

Publisher Copyright:
© 2023 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH.

Keywords

  • epitaxial lateral overgrowth
  • GaO
  • hydrogen plasma treatment
  • metastable polymorphs
  • wide-bandgap semiconductors

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering

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