High-performance ε-Ga2O3 solar-blind ultraviolet photodetectors on Si (100) substrate with molybdenum buffer layer

Abstract

ε-Ga2O3 (002) thin films were successfully grown on Si (100) substrate by metalorganic chemical vapor deposition (MOCVD). The crystal structure, chemical composition, and surface morphology of ε-Ga2O3 (002) thin films were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The lattice mismatch between Si and ε-Ga2O3 was effectively reduced by inserting Molybdenum (Mo) buffer layer. Quasi-vertical ε-Ga2O3 Schottky barrier diode (SBD) solar-blind photodetectors grown on Si (100) substrate with the Mo buffer layer were fabricated and characterized. The device has a photo-to-dark current ratio (PDCR) of 1.57 × 103, a responsivity (R) of 243.14 A·W-1, a detectivity (D*) of 1.83 × 1017 Jones (cm·Hz1/2 W−1), and an excellent response time due to improved crystal quality and the vertical device structure. This work provides an important reference for the heteroepitaxial growth of ε-Ga2O3 on Si, which is beneficial to the development of low-cost, high-performance ε-Ga2O3 optoelectronic and power electronic devices.