Modified band alignment at multilayer MoS2/Al2O3 heterojunctions by nitridation treatment

Abstract

Interface engineering plays a decisive role in the two-dimensional material/high-κ oxide heterojunction-based devices. In this work, the effects of NH3 plasma interface treatment on the energy band alignment at multilayer MoS2/Al2O3 heterostructures were explored using x-ray photoelectron spectroscopy. A type-Ⅰ band alignment was formed with valence band offset (VBO) and conduction band offset (CBO) about 3.67 eV and 2.33 eV, respectively. Significantly, the CBO was enlarged by about 0.45 eV after the plasma treatment, which was mainly attributed to the increased separation between the Al 2p core-level energy and valence band maximum. This interesting finding provides a significant guidance for the band adjustment at the interface and further applications of multilayer MoS2 in electronic devices.