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

Researchers from the State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences have published a dissertation titled " Two-step growth of β-Ga₂O₃ on c-plane sapphire using MOCVD for solar-blind photodetector " in Journal of Semiconductors.

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 @ 254nm 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.

Fig. 1. (a) XRD ω−2θ scan and (b) FWHM of rocking curve for β-Ga₂O₃ films grown at different TB. Inset shows the XRD ω scan for films.

Fig. 2. (a) AFM images and (b) RMS roughness of β-Ga₂O₃ films, (c) film thicknesses obtained from the cross-sectional SEM. Inset shows the cross-sectional image of film grown at T_B = 700 °C.

Paper Link：http://www.jos.ac.cn/en/article/id/3aa3f6c4-2d6c-4339-8c13-09f43038ae1d?viewType=HTML