Influence of O2 pulse on the β-Ga2O3 films deposited by pulsed MOCVD

Abstract

β-Ga2O3 films were deposited on c-plane sapphire substrates by pulsed MOCVD, and the TEGa and O2 were alternately delivered to the reactor as two pulses. During the growth process, the Ga pulse was kept at 0.1 min, and the O2 pulse was set at 0.1, 0.2 and 0.3 min, respectively. XRD showed that the β-Ga2O3 films still grew preferentially along the (−201) crystal plane family, and no other crystal orientations were observed. The β-Ga2O3 films had uniform surface morphology, and grain size increased slightly with the increasing O2 pulse. XRD rocking curves indicated that the β-Ga2O3 film deposited at 0.2 min pulse of O2 had the best crystalline quality. The PL spectra of all β-Ga2O3 films presented the broad UV–visible photoluminescence region from 250 to 800 nm. Three obvious main photoluminescence peaks were observed, corresponding to UV, blue and green emission, respectively. Photodetector was fabricated from the β-Ga2O3 film deposited at 0.2 min pulse of O2, showing stable photoelectric performance, and the photo-dark current ratio was as high as 1.7 × 105 at 15 V.