ε-Ga2O3 thin films grown by metal-organic chemical vapor deposition and its application as solar-blind photodetectors

In this work, hetero-epitaxy of ε-Ga 2 O 3 thin films are grown on c-plane sapphire by metal-organic chemical vapor deposition (MOCVD). Different oxygen precursors of deionized water (H 2 O) or high-purity nitrous oxide (N 2 O) gas are used and their impacts on crystal structure, optical absorption, cathodoluminescence, and photoelectric properties have been intensively studied. X-ray diffraction (XRD) analysis has shown that the ε-Ga 2 O 3 epilayers are highly (001) oriented and the VI/III ratio is a critical growth parameter for the phase purity of Ga 2 O 3 . Cathodoluminescence (CL) measurements reveal that the luminescence peaks appear in the violet–blue–green region. A general increase of luminescence intensity is evidenced for samples grown using H 2 O as oxygen sources, which is explained by higher radiation recombination. Deep-ultraviolet (DUV) photodetectors with metal-semiconductor-metal (MSM) structure have been fabricated based on the ε-Ga 2 O 3 thin films. The comparison of the device performances shows that faster response speed and higher responsivity are obtained for the device based on the ε-Ga 2 O 3 grown by H 2 O as precursors, which indicates the potential of high quality ε-Ga 2 O 3 to be applied in DUV photodetectors. • Hetero-epitaxy of ε-Ga 2 O 3 thin films on C-plane sapphire substrate were carried out by metal-organic chemical vapor deposition (MOCVD) with different oxygen precursors. • The ε-Ga 2 O 3 thin films grown by H 2 O as oxygen precursors which show better crystallinity and fewer defects density. • Performance enhancements are demonstrated in the SBPDs which based on ε-Ga 2 O 3 thin films grown with H 2 O precursor. It shows that ε-Ga 2 O 3 thin films grown with H 2 O precursors reveal excellent DUV detection performance, which is promising for the realization of high-sensitivity and fast-response solar-blind photodetectors.