β-Ga₂O₃ Thin Films via an Inorganic Sol-Gel Spin Coating: Preparation and Characterization

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Beta-gallium oxide (β-Ga₂O₃) is a promising ultra-wide bandgap semiconductor for UV detectors and high-power electronics.
• Cost-effective, large-area thin film fabrication of β-Ga₂O₃ remains a significant challenge for industrial applications.

Purpose of the Study:

• To develop a low-cost, efficient method for producing high-quality β-Ga₂O₃ thin films.
• To investigate the structural, morphological, and optical properties of β-Ga₂O₃ films prepared via inorganic solution reaction and spin-coating.

Main Methods:

• β-Ga₂O₃ thin films were synthesized using an inorganic solution reaction followed by spin-coating onto sapphire and quartz substrates.
• Films were subjected to post-annealing treatments at varying temperatures.
• Characterization involved X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectrophotometry.

Main Results:

• Optimized spin-coating cycles (ten) and annealing at 800 °C produced smoother β-Ga₂O₃ films on sapphire with preferred [-201] orientation.
• Films exhibited high transmittance (>85%) for wavelengths above 400 nm.
• Bandgaps of 4.8 eV and 4.98 eV were measured for films annealed at 800 °C and 1000 °C, respectively, on sapphire substrates.

Conclusions:

• Sapphire substrates show superior compatibility for high-quality β-Ga₂O₃ film growth compared to quartz.
• The developed spin-coating method offers a cost-effective and scalable approach for fabricating β-Ga₂O₃ films for optoelectronic devices.