High temperature phases with wurtzite-derived structure in Zn2LiGaO4–ZnO alloy system

Masao Kita, Tomoaki Fukada, Shu Yamaguchi, Takahisa Omata

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

We investigated the structural phase transformations of Zn2LiGaO4, which is a quaternary oxide semiconductor with a wide band gap of 4.0 eV, and its alloys with ZnO by using in-situ high-temperature X-ray diffraction (XRD), room-temperature XRD and selected-area electron diffraction of samples quenched from high temperatures of >873 K. Three types of phases with the wurtzite-derived structure were found in the y(Zn2LiGaO4)1/4–(1−y)ZnO alloy system. First is the low-temperature phase, phase I, in which constituent cations are ordered similarly to those in a Cd2AgGaS4-type structure. Phase I has an incommensurate modulation vector of 1.04b* and is stable at <1070 K and compositions of 0.96 ≤ y ≤ 1 and is stable at room temperature for y = 0.92. The second phase, phase II, appears at intermediate temperatures of 773–1373 K at 0.96 ≤ y ≤ 1, and its incommensurate modulation vector is 1.08b*. Phase III, which has no long-range cation ordering but still has short-range cation ordering, is stable for 0.92 ≤ y ≤ 1 at high temperatures and for 0.2 ≤ y < 0.92 from room temperature to high temperatures. We discuss the driving force of the transformations among the three phases in terms of their crystal structure and the mismatch in thermal expansion between –Zn–O–Zn–O– and –Li–O–Ga–O– linkages.

Original languageEnglish
Pages (from-to)69-76
Number of pages8
JournalJournal of Alloys and Compounds
Volume688
DOIs
Publication statusPublished - 2016 Jan 1

Keywords

  • Incommensurate modulation
  • Phase transformation
  • Thermal expansion
  • Wurtzite-derived structure

ASJC Scopus subject areas

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

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