Band offsets and electronical properties of the Ga2O3/FTO heterojunction via transferring free-standing Ga2O3 onto FTO/glass

The determination of band offsets is crucial in optimizing Ga2O3-based devices, since the band alignment types could determine the operations of devices due to the restriction of carriers transports across the heterogeneous interfaces. In this work, the band offsets of the Ga2O3/FTO heterojunction are studied by using X-ray photoelectron spectroscopy (XPS) based on Kraut's method, which suggests a staggered type- alignment with Ⅱ a conduction band offset (ΔEc) of 1.66 eV and a valence band offset (ΔEv) of -2.41 eV. Furthermore, the electronical properties of the Ga2O3/FTO heterostructure are also measured both in the dark and under ultraviolet (UV) illuminated conditions (254 nm UV light). Overall, this work can provide a meaningful guidance for designing and constructing oxide hetero-structured devices based on wide-bandgap semiconducting Ga2O3.