Preparation of β-Ga2O3/ε-Ga2O3 type II phase junctions by atmospheric pressure chemical vapor deposition

We synthesized beta-Ga2O3/epsilon-Ga2O3 phase junctions by exploiting distinct crystalline phases in gallium oxide through a one-step atmospheric-pressure chemical vapor deposition process on sapphire substrates, adjusting parameters such as temperature and gas flow rate accordingly. The coexistence of these two crystalline phases was verified via X-ray diffraction (XRD) and Raman spectroscopy analyses, while optical microscopy provided visual evidence regarding surface morphology changes throughout phase junction formation stages. Furthermore, we utilized a UV-visible spectrophotometer to quantify the bandgap and integrated this data with X-ray photoelectron spectroscopy (XPS) analysis of core level peaks and valence band spectra in order to construct an energy level structure for the beta-Ga2O3/epsilon-Ga2O3 phase junction. Our findings demonstrate that this phase junction exhibits a type II energy band alignment, with measured valence and conduction band offsets of 0.54 eV and 0.41 eV respectively. This discovery holds significant implications for self-powered photodetectors utilizing gallium oxide as well as other potential applications.