Low-temperature grown wurtzite InxGa1−xN thin films via hollow cathode plasma-assisted atomic layer deposition

Date
2015-08
Advisor
Instructor
Source Title
Journal of Materials Chemistry C
Print ISSN
2050-7534
Electronic ISSN
Publisher
Royal Society of Chemistry
Volume
3
Issue
37
Pages
9620 - 9630
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
Abstract

Herein, we report on atomic layer deposition of ternary InxGa1−xN alloys with different indium contents using a remotely integrated hollow cathode plasma source. Depositions were carried out at 200 °C using organometallic Ga and In precursors along with N2/H2 and N2 plasma, respectively. The effect of In content on structural, optical, and morphological properties of InxGa1−xN thin films was investigated. Grazing incidence X-ray diffraction showed that all InxGa1−xN thin films were polycrystalline with a hexagonal wurtzite structure. X-ray photoelectron spectroscopy depicted the peaks of In, Ga, and N in bulk of the film and revealed the presence of relatively low impurity contents. In contents of different InxGa1−xN thin films were determined by energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Transmission electron microscopy also confirmed the polycrystalline structure of InxGa1−xN thin films, and elemental mapping further revealed the uniform distribution of In and Ga within the bulk of InxGa1−xN films. Higher In concentrations resulted in an increase of refractive indices of ternary alloys from 2.28 to 2.42 at a wavelength of 650 nm. The optical band edge of InxGa1−xN films red-shifted with increasing In content, confirming the tunability of the band edge with alloy composition. Photoluminescence measurements exhibited broad spectral features with an In concentration dependent wavelength shift and atomic force microscopy revealed low surface roughness of InxGa1−xN films with a slight increase proportional to In content.

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Keywords
Atomic force microscopy, Atomic layer deposition, Cathodes, Deposition, Electrodes, Electron sources, Energy dispersive spectroscopy, Gallium, Gallium alloys, High resolution transmission electron microscopy, Indium, Indium alloys, Metallic films, Organometallics, Photoelectrons, Photons, Pulsed laser deposition, Refractive index, Surface roughness, Temperature, Transmission electron microscopy, X ray diffraction, X ray photoelectron spectroscopy, X ray spectroscopy, Zinc sulfide, Concentration-dependent, Grazing incidence X-ray diffraction, Hexagonal wurtzite structure, Low surface roughness, Low-temperature grown, Morphological properties, Photoluminescence measurements, Polycrystalline structure, Thin films
Citation
Published Version (Please cite this version)