Cathodoluminescence and field emission from GaN/MgAl2O 4 grown by metalorganic chemical vapor deposition: Substrate-orientation dependence

Gang He, Toyohiro Chikyo, Xiaoshuang Chen, Hanshuang Chen, Jiangwei Liu, Zhaoqi Sun

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

GaN films with single-crystalline and polycrystalline structures were deposited by metalorganic chemical vapor deposition (MOCVD) on (111) and (100) MgAl2O4 substrates modified by chemical etching and thermal passivation. The oriented GaN films on the as-processed (111) MgAl 2O4 substrate revealed broad visible emission band bands at 3.2 eV and a sharp luminescence peak centered at 1.8 eV in room temperature cathodoluminescence measurements, which can be attributed to the recombination of donor-acceptor pairs and GaN-related emission, respectively. Field emission (FE) measurements demonstrated that the oriented nanostructured 150 nm-thick GaN film on the as-processed (111) MgAl2O4 substrate has an ultralow turn-on-field of 4.29 V μm-1 at 10 nA cm-2 and a stable emission of 0.028 mA cm-2 with 5% current density fluctuation for 22 h without any degradation. Compared to GaN films on as-processed (100) MgAl2O4 substrate, the mechanism for the improved performance in optical and FE properties of the GaN film on as-processed (111) MgAl2O4 substrate has been investigated in detail.

Original languageEnglish
Pages (from-to)238-245
Number of pages8
JournalJournal of Materials Chemistry C
Volume1
Issue number2
DOIs
Publication statusPublished - 2013 Jan 14
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

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