Journal article
Chemical Vapor Deposition of Hexagonal Gallium Selenide and Telluride Films from Cubane Precursors: Understanding the Envelope of Molecular Control
Chemistry of materials, Vol.9(12), pp.3037-3048
12/16/1997
DOI: 10.1021/cm9703886
Abstract
Gallium selenide (GaSe) thin films have been grown at 325−370 °C by atmospheric pressure metal−organic chemical vapor deposition (AP-MOCVD) using the single-source precursors [(R)Ga(μ3-Se)]4 (R = CMe3, CEtMe2, and CEt2Me). In contrast, the growth of gallium telluride from [(R)Ga(μ3-Te)]4 is accomplished at 285−310 °C by low-pressure metal−organic chemical vapor deposition (LP-MOCVD). Characterization of the films by Auger electron spectroscopy (AES), Rutherford backscattering (RBS), and wavelength-dispersive spectroscopy (WDS) microprobe analysis shows all the films to have Ga:E (E = Se, Te) compositions of 1:1 with a low degree of impurities (C < 2%; O < 0.1%). From X-ray diffraction (XRD) and transmission electron microscopy (TEM) the GaSe and GaTe films were found to be polycrystalline hexagonal layered GaE structures, with a preferred c-axis orientation independent of substrate. For GaSe this represents the thermodynamically stable phase, while hexagonal GaTe is a metastable phase that converts to the thermodynamic monoclinic form on annealing at 500 °C. Diffraction results yield appropriate lattice parameters of a = 4.1 Å (TEM) and c = 16.38 Å (XRD) for hexagonal GaTe. Crystallite and particle size measurements reveal that the as-deposited films consist of oriented ca. 10 nm crystalline particles. The formation of these hexagonal layered structures is proposed to occur as a consequence of the fragmentation of the cubane's Ga4E4 core during deposition, and the formation of trimeric “Ga3E3” building blocks.
Details
- Title: Subtitle
- Chemical Vapor Deposition of Hexagonal Gallium Selenide and Telluride Films from Cubane Precursors: Understanding the Envelope of Molecular Control
- Creators
- Edward G GillanAndrew R Barron
- Resource Type
- Journal article
- Publication Details
- Chemistry of materials, Vol.9(12), pp.3037-3048
- Publisher
- American Chemical Society
- DOI
- 10.1021/cm9703886
- ISSN
- 0897-4756
- eISSN
- 1520-5002
- Language
- English
- Date published
- 12/16/1997
- Academic Unit
- Chemistry
- Record Identifier
- 9984001172802771
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