EXPLORING GALLIUM OXIDE (GA2O3) NANOWIRES-A TECHNICAL REPORT

Abstract

Background: Gallium oxide (Ga₂O₃) nanowires have attracted growing attention for their unique physicochemical properties, including high thermal stability, wide band gap (~4.9 eV), and strong photoluminescence. These characteristics render them ideal candidates for high-power electronics, ultraviolet photodetectors, gas sensors, and optoelectronic applications. Despite significant advancements, most conventional synthesis techniques remain limited by prolonged processing times, low growth rates, and difficulty in scalability, presenting obstacles to their widespread industrial integration.

Objective: This study aimed to evaluate and compare multiple synthesis techniques for fabricating high-quality Ga₂O₃ nanowires, focusing on optimizing growth conditions, structural integrity, and functional performance to enable scalable and application-ready production.

Methods: Ga₂O₃ nanowires were synthesized using thermal evaporation, physical vapor deposition (PVD), chemical vapor deposition (CVD), hydrothermal, and microwave plasma techniques. Structural and morphological characterization was conducted using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Electrical, optical, and gas-sensing performance was evaluated using field-effect transistor (FET) setups, photoluminescence spectroscopy, and voltamperometric sensing against O₂ and CO gases.

Results: The nanowires displayed an average diameter of ~60 nm and lengths exceeding 100 µm. XRD confirmed a monoclinic β-Ga₂O₃ phase, while HRTEM revealed distinct atomic-level twinning. Photoluminescence peaks at 446 nm (2.78 eV) and 465 nm were observed. FET-based electrical testing yielded resistivity values ranging from 10⁴–10⁶ Ω·cm. Gas sensors showed peak responses to O₂ at 300 °C and CO at 200 °C, with rapid response/recovery times and high signal-to-noise ratios.

Conclusion: Microwave plasma and vapor–solid methods proved most effective for producing uniform, defect-free Ga₂O₃ nanowires. These approaches offer promising routes toward scalable, high-performance nanowire-based devices for sensing and optoelectronic applications.