Growth and Characterization of (InGa)2O3 Alloys
Date
2018-08
Authors
Samuels, Brian
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Abstract
To create the next generation of power devices, new materials are being developed for use as wide bandgap semiconductors. Wide bandgap oxides are receiving attention as their properties are conducive to improved power and high breakdown devices. The indium gallium oxide alloy makes it one of the candidates that can be used in heterostructures in which the electrical and optical properties can be tuned. While research has been concentrated on the development and understanding of the properties of In<sub>2</sub>O<sub>3</sub> and Ga<sub>2</sub>O<sub>3</sub> thin films, there is a need to develop an understanding of the structure and behavior of alloys composed of these metal oxides. This research demonstrates the growth of the cubic form of (In<sub>x</sub>Ga<sub>1-x</sub>)<sub>2</sub>O<sub>3</sub> for x = 0.6, 0.8, and 1.0 on sapphire (0001) substrates using pulsed laser deposition. Single crystal films are identified by peaks corresponding to the (222) and (444) planes using high-resolution x-ray diffraction. The optical constants (n, k) are found to be between 1.9-2.0 and 0.0005-0.5 respectively using spectroscopic ellipsometry. The bandgap of the alloys is shown to be 3.68-3.86 eV, with the increase due to an increased gallium composition. Mobility and resistivity of the alloys are ~10<sup>19</sup>-10<sup>20</sup> cm<sup>2</sup>/V<sup>-1</sup>s<sup>-1</sup> and ~10<sup>-3</sup>-10<sup>-2</sup> Ω·cm respectively and vary as a result of partial oxygen pressure during growth. This high carrier concentrations with wide bandgap also makes this material useful for transparent conductors and UV applications.
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Keywords
Indium oxide, Gallium oxide, PLD
Citation
Samuels, B. (2018). <i>Growth and characterization of (InGa)2O3 alloys</i> (Unpublished thesis). Texas State University, San Marcos, Texas.