Band alignment of 2 H-phase two-dimensional MoS2/graphene oxide van der Waals heterojunction

초록

Two-dimensional van der Waals heterojunctions have been of particular interest owing to their superior properties and advantages of integrating the enhanced optoelectronic devices. Here, we demonstrate the band alignment at 2 H-phase molybdenum disulfide (MoS2)/graphene oxide (GO) van der Waals hetero-junction and experimentally determine the valence band offset (VBO) using X-ray photoelectron spectro-scopy. The chemical and optical properties of MoS2 and GO nanosheet films are investigated by Raman and UV-Vis spectroscopy, and the VBO is also verified by Anderson's model using ultraviolet photoelectron spectroscopy. Based on the results, type II band alignment at MoS2/GO heterojunction is revealed, where conduction band offset (0.21 +/- 0.1 eV) is determined to be much smaller than VBO (2.19 +/- 0.1). Further, charge transport across the MoS2/GO interface is investigated, leading to the p-type doping of MoS2 induced by electron-withdrawing functional groups of GO. Considering that modulation of bandgap can be achieved by engineering the thickness of MoS2 and degree of reduction in GO, the band alignment of MoS2/GO heterojunction can be controlled depending on the target devices. Thus, our proposed work provides a better understanding of band alignment at the MoS2/GO heterojunction which is essential for developing next-generation optoelectronic applications. (c) 2022 Elsevier B.V. All rights reserved.

키워드