Nanostructural characterization and two-dimensional electron-gas properties in high-mobility AlGaN/AlN/GaN heterostructures grown on epitaxial AlN/sapphire templates

Makoto Miyoshi, Takashi Egawa, Hiroyasu Ishikawa, Kei Ichiro Asai, Tomohiko Shibata, Mitsuhiro Tanaka, Osamu Oda

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33 Citations (Scopus)

Abstract

Al0.26 Ga0.74 NAlNGaN heterostructures with a 1 nm -thick AlN interfacial layer were grown on epitaxial AlN/sapphire templates by metal-organic vapor phase epitaxy, and they exhibited excellent film qualities and very high electron mobilities, such as over 2100 cm2 V s at room temperature and over 25 000 cm2 V s at 15 K with a two-dimensional electron-gas (2DEG) density of approximately 1× 1013 cm2. Cross-sectional transmission electron microscopy images revealed that the thin AlN layer with a thickness of 1 nm is continuously grown between AlGaN and GaN layers with atomically abrupt and flat interfaces. The experimental and calculated results for 2DEG transport properties indicated that an AlN interfacial layer between AlGaN and GaN layers effectively suppresses alloy disorder scattering and that epitaxial AlN/sapphire templates largely contribute to the high electron mobility because they allow for the realization of a high-quality GaN channel with a low dislocation density and a smooth interface.

Original languageEnglish
Article number063713
JournalJournal of Applied Physics
Volume98
Issue number6
DOIs
Publication statusPublished - 2005 Sep 15

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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