High-performance β-Ga2O3 solar-blind ultraviolet photodetectors epitaxially grown on (110) TiO2 substrates by metalorganic chemical vapor deposition

High-quality (100)-oriented beta-Ga2O3 films were successfully grown on (110) TiO2 substrates by metalorganic chemical vapor deposition (MOCVD) for the first time. Crystal structure, chemical composition, and surface morphology of the epitaxial beta-Ga2O3 films were systematically investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscope (AFM). The epitaxial relationship between the beta-Ga2O3 film and the TiO2 substrate was identified as beta-Ga2O3 (100)//TiO2 (110) with beta-Ga2O3 [001]//TiO2 [110] and beta-Ga2O3 [010]//TiO2 [001]. These material characterizations confirmed that the beta-Ga2O3 film grown at 950 degrees C exhibited the highest crystalline quality and the smoothest surface. Furthermore, these beta-Ga2O3 films were then used to fabricate solar-blind photodetectors (PDs) based on a metal-semiconductor-metal (MSM) structure. Due to the beta-Ga2O3 film's best material and surface morphology grown at 950 degrees C, the beta-Ga2O3 PDs showed the best performance with a large photocurrent of 85.3 mu A, a responsivity of 2.56 A W-1, and a detectivity of 5 x 10(11) Jones. This work explores a new TiO2 substrate for the heterogeneous epitaxy of beta-Ga2O3 films, and opens the door for the development of beta-Ga2O3 photonics and electronics on cost-effective mass-producible substrates.

Automated summary

High-quality (100)-oriented beta-Ga2O3 films were successfully grown on (110) TiO2 substrates for the first time using MOCVD. The films exhibited the highest crystalline quality and smoothest surface at 950 degrees C, leading to the best performance in solar-blind photodetectors. This work opens up possibilities for developing beta-Ga2O3 photonics and electronics on cost-effective mass-producible substrates.