Control of polarity of ZnO films grown by plasma-assisted molecular-beam epitaxy: Zn- and O-polar ZnO films on Ga-polar GaN templates

Soon Ku Hong, Takashi Hanada, Hang Ju Ko, Yefan Chen, Takafumi Yao, Daisuke Imai, Kiyoaki Araki, Makoto Shinohara

Research output: Contribution to journalArticlepeer-review

62 Citations (Scopus)

Abstract

We report on the growth of polarity-controlled ZnO films by plasma-assisted molecular-beam epitaxy. Different polar (Zn- and O-polar) ZnO films on unipolar (Ga-polar) GaN epilayers are selectively grown. Polarity of ZnO films is evaluated by coaxial impact collision ion scattering spectroscopy. Zn preexposure prior to ZnO growth results in Zn-polar ZnO films (Zn face), while O-plasma preexposure leads to the growth of O-polar ZnO films (O face). High-resolution transmission electron microscopy reveals the formation of an interface layer between ZnO and GaN epilayers in O-plasma preexposed samples, while no interface layer is observed in Zn preexposed samples. The interface layer is identified as single crystalline, monoclinic Ga2O3. We propose models for interface configurations at ZnO/GaN heterointerfaces, which can successfully explain the different polarities of the ZnO films.

Original languageEnglish
Pages (from-to)3571-3573
Number of pages3
JournalApplied Physics Letters
Volume77
Issue number22
DOIs
Publication statusPublished - 2000 Nov 27

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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