Enhanced self-powered solar blind deep UV photodetector based on β-Ga2O3 homojunction with the synergistic regulation of Sn heavy doping and Schottky junctions

In this paper, the homoepitaxial growth of high-quality β-Ga2O3 thin films on both intrinsic and Sn-doped β-Ga2O3 (011) single crystal substrates without hillock and groove were successfully realized by metal organic chemical vapor deposition technology. High resolution X-ray diffraction results demonstrated that the full width at half maximum of the rocking curves for the epitaxial films grown on undoped and Sn-doped substrates are 62.7 and 139 arc seconds, respectively. Atomic force microscopy results demonstrated a root mean square roughness (RMS) of the film surface at merely 0.86 nm and 1.32 nm, signifying a smooth and compact surface morphology. A strong self-powered photo responsing characteristics has been realized in an Au/Ga2O3/Ti Schottky-Ohm metal-semiconductor-metal (MSM) UV photodetector with a vertical structure. Compared to the devices prepared on the intrinsic β-Ga2O3 substrates, the devices grown on Sn-doped substrates exhibit significantly enhanced photoelectric performance at 0 V, achieving a responsivity of 14.8 mA/W and a detectivity of 6.3×1013 Jones. The rise/decay time is 0.32/3.1 ms, respectively. The device’s exceptional performance is primarily due to the double built-in electric fields at the Au/Ga2O3 Schottky junction and the Ga2O3/Sn: Ga2O3 n+/i homojunction. This configuration accelerates photogenerated carrier separation and transport, suppresses dark current, and reduces carrier recombination probability, enhancing overall device performance. The above results indicate that the device structure with the synergistic regulation of homojunctions and Schottky junctions provides an effective design idea for realizing high-performance, self-powered β-Ga2O3-based solar-blind ultraviolet photodetectors.