Two-step growth of β-Ga2O3 on c-plane sapphire using MOCVD for solar-blind photodetector

Abstract

In this work, a two-step metal organic chemical vapor deposition (MOCVD) method was applied for growing β-Ga₂O₃ film on c-plane sapphire. Optimized buffer layer growth temperature (T _B) was found at 700 °C and the β-Ga₂O₃ film with full width at half maximum (FWHM) of 0.66° was achieved. A metal−semiconductor−metal (MSM) solar-blind photodetector (PD) was fabricated based on the β-Ga₂O₃ film. Ultrahigh responsivity of 1422 A/W @ 254 nm and photo-to-dark current ratio (PDCR) of 10⁶ at 10 V bias were obtained. The detectivity of 2.5 × 10¹⁵ Jones proved that the photodetector has outstanding performance in detecting weak signals. Moreover, the photodetector exhibited superior wavelength selectivity with rejection ratio (R _{250 nm}/R _{400 nm}) of 10⁵. These results indicate that the two-step method is a promising approach for preparation of high-quality β-Ga₂O₃ films for high-performance solar-blind photodetectors.