Type-II Interface Band Alignment in the vdW PbI<sub>2</sub>–MoSe<sub>2</sub> Heterostructure
Junting Xiao, Lei Zhang, Hui Zhou, Ziyi Shao, Jinxin Liu, Yuan Zhao, Youzhen Li, Xiaoliang Liu, Haipeng Xie, Yongli Gao, Jia‐Tao Sun, Andrew T. S. Wee, Han Huang
Abstract
Energy band alignments at heterostructure interfaces play key roles in device performance, especially between two-dimensional atomically thin materials. Herein, van der Waals PbI2–MoSe2 heterostructures fabricated by in situ PbI2 deposition on monolayer MoSe2 are comprehensively studied using scanning tunneling microscopy/spectroscopy, atomic force microscopy, photoemission spectroscopy, and Raman and photoluminescence (PL) spectroscopy. PbI2 grows on MoSe2 in a quasi layer-by-layer epitaxial mode. A type-II interface band alignment is proposed between PbI2 and MoSe2 with the conduction band minimum (valence band maximum) located at PbI2 (MoSe2), which is confirmed by first-principles calculations and the existence of interfacial excitons revealed using temperature-dependent PL. Our findings provide a scalable method to fabricate PbI2–MoSe2 heterostructures and new insights into the electronic structures for future device design.