High electron mobility Zn polar ZnMgO/ZnO heterostructures grown by molecular beam epitaxy

H. Tampo, K. Matsubara, A. Yamada, H. Shibata, P. Fons, M. Yamagata, H. Kanie, S. Niki

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30 Citations (Scopus)

Abstract

A drastic enhancement of electron mobility was observed in Zn polar ZnMgO/ZnO heterostructures (ZnMgO on ZnO) grown by radical source molecular beam epitaxy (MBE) due to the formation of a two-dimensional electron gas (2DEG). The electron mobility dramatically increased with increasing Mg composition for a ZnMgO layer and the electron mobility (μ ∼ 250 cm2 / Vs) at RT reached a value more than twice that of an undoped ZnO layer (μ ∼ 100 cm2 / Vs). Reflection high energy electron diffraction (RHEED) patterns taken during the growth of the ZnMgO layer remained streaky; X-ray diffraction measurements showed no evidence of phase separation for up 44% Mg composition. Temperature-dependent Hall measurements of ZnMgO/ZnO heterostructures also exhibited properties associated with well-defined heterostructures. The Hall mobility increased monotonically with decreasing temperature, reaching a value of 2750 cm2 / Vs at 4 K. Zn polar "ZnMgO on ZnO" structures are easy to adapt to top-gate devices. These results open new possibilities for high electron mobility transistors (HEMTs) using ZnO-based materials.

Original languageEnglish
Pages (from-to)358-361
Number of pages4
JournalJournal of Crystal Growth
Volume301-302
Issue numberSPEC. ISS.
DOIs
Publication statusPublished - 2007 Apr
Externally publishedYes

Keywords

  • A1. Crystallographic polarity
  • A1. Heterostructure
  • A1. Two-dimensional electron gas (2DEG)
  • A3. molecular beam epitaxy
  • B1. ZnMgO
  • B1. ZnO

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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