Band alignment of atomic layer deposited TiO2/multilayer MoS2 interface determined by x-ray photoelectron spectroscopy

High-resolution x-ray photoelectron spectroscopy (XPS) was employed to characterize the energy band alignment between TiO2/multilayer (ML)-MoS2. The TiO2 film and ML-MoS2 film was grown by an atomic layer deposition (ALD) and chemical vapor deposition (CVD), respectively. The effect of CHF3 plasma treatment on the band alignment between TiO2/ML-MoS2 was evaluated. It was found that the valence band offset (VBO) and a conduction band offset (CBO) of TiO2/ML-MoS2 interface was changed from 2.28 eV to 2.51 eV, and from 0.28 eV to 0.51 eV, respectively for the sample with CHF3 plasma treatment. With the CHF3 plasma treatment, the down-shift of Mo 3d core level binding energy results in a bend-up of energy potential on the MoS2 side, leading to 0.23 eV ΔEC difference between the control and the sample with CHF3 plasma treatment, which is caused by the interfacial layer in rich of F element. The physics details of the band alignment at TiO2/ML-MoS2 interface will provide a guide for the MoS2 based electronic device design.