Growth of β-Ga2O3 Single-Crystal Microbelts by the Optical Vapor Supersaturated Precipitation Method

Monoclinic β-Ga2O3 microbelts were successfully fabricated using a one-step optical vapor supersaturated precipitation method, which exhibited advantages including a free-standing substrate, prefect surface, and low cost. The as-grown microbelts possessed a well-defined geometry and perfect crystallinity. The dimensions of individual β-Ga2O3 microbelts were a width of ~50 μm, length of ~5 mm, and thickness of ~3 μm. The SEM, XRD, HRTEM, XPS, and Raman spectra demonstrated the high single-crystalline structure of β-Ga2O3 microbelts. Twelve frequency modes were activated in Raman spectra. The optical band gap of the β-Ga2O3 microbelt was calculated to be ~4.45 eV. Upon 266 nm excitation, 2 strong UV emissions occurred in photoluminescence spectra through the radiative recombination of self-trapped excitons, and the blue emission band was attributed to the presence of donor-acceptor-pair transition. The individual β-Ga2O3 microbelt was employed as metal-semiconductor-metal deep-ultraviolet photodetector, which exhibits the photoresponse under 254 nm. This work provides a simple and economical route to fabricate high-quality β-Ga2O3 single-crystal microbelts, which should be a potential synthetic strategy for ultra-wide bandgap semiconductor materials.