Optical and Structural Characterization of Cu-Doped Ga<sub>2</sub>O<sub>3</sub> Nanostructures Synthesized via Hydrothermal Method

In this study, we investigate the optical and structural properties of Cu-doped <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> nanostructures synthesized via a hydrothermal method, followed by annealing in ambient O<sub>2</sub>. Different Cu doping concentration...

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Bibliographic Details
Main Authors: Jiwoo Kim, Heejoong Ryou, Janghun Lee, Sunjae Kim, Wan Sik Hwang
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Inorganics
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Online Access:https://www.mdpi.com/2304-6740/13/7/231
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Summary:In this study, we investigate the optical and structural properties of Cu-doped <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> nanostructures synthesized via a hydrothermal method, followed by annealing in ambient O<sub>2</sub>. Different Cu doping concentrations (0, 1.6, and 4.8 at.%) are introduced to examine their effects on the crystal structure, chemical state, and optical bandgap of <i>β</i>-Ga<sub>2</sub>O<sub>3</sub>. X-ray diffraction (XRD) analysis reveals that the host <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> crystal structure is preserved at lower doping levels, whereas secondary phases (Ga<sub>2</sub>CuO<sub>4</sub>) appear at higher doping concentrations (4.8 at.%). X-ray photoelectron spectroscopy (XPS) confirms the presence of Cu<sup>2+</sup> ions in both lattice substitution sites and surface-adsorbed hydroxylated species (Cu(OH)<sub>2</sub>). The optical bandgap of <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> is found to decrease with increasing Cu concentration, likely due to the formation of localized states or secondary phases. These findings demonstrate the tunability of the optical properties of <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> via Cu doping, providing insights into the incorporation mechanisms and their impact on structural and electronic properties.
ISSN:2304-6740