Effects of Components Modulation on the Type of Band Alignments for PbI<sub>2</sub>/WS<sub>2</sub> van der Waals Heterostructure
Meng-Ya Qian, Zhuo‐Liang Yu, Qiang Wan, Peng-Bin He, Biao Liu, Junliang Yang, Chunmei Xu, Meng‐Qiu Cai
Abstract
Building semiconductor‐based van der Waals heterostructures (vdWHs) based on 2D materials can integrate the excellent properties of single materials to promote the development of an application for optoelectronics. In general, semiconductor‐based vdWHs have different types of band alignments related to the performance of equipment. However, it is greatly challenging to achieve controllable types of band alignment for a single heterojunction. Herein, the electronic and optical properties of the lead iodide/tungsten disulfide (PbI 2 /WS 2 ) heterostructure are investigated systematically by density functional theory (DFT) calculation. A Type‐I–Type‐II transition of band alignments in PbI 2 /WS 2 vdWHs is achieved by partly replacing the S atom in WS 2 monolayer with Se atom. The reason lies in the change of band structure which can be attributed to a transformation in the conduction band minimum (CBM) from the W 5d and S 3p states to Pb 6p orbital in PbI 2 /WS 2 vdWHs. Moreover, the averaged hole carrier effective mass of the PbI 2 /WSe 2 vdWH has a minimum. The results may provide a direction to explore the transformation in band alignment in semiconductor‐based vdWHs for potential photoelectric applications.