Type-II Interface Band Alignment in the vdW PbI2-MoSe2 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

doi:10.1021/acsami.0c04985

Type-II Interface Band Alignment in the vdW PbI₂-MoSe₂ Heterostructure

ACS Appl Mater Interfaces. 2020 Jul 15;12(28):32099-32105. doi: 10.1021/acsami.0c04985. Epub 2020 Jun 30.

Authors

Junting Xiao¹, Lei Zhang², Hui Zhou³, Ziyi Shao¹, Jinxin Liu¹, Yuan Zhao¹, Youzhen Li¹, Xiaoliang Liu¹, Haipeng Xie¹, Yongli Gao^{1

4}, Jia-Tao Sun^{3

5}, Andrew T S Wee², Han Huang¹

Affiliations

¹ Hunan Key Laboratory of Super-Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, P. R. China.
² Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore.
³ Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
⁴ Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, United States.
⁵ School of Information and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing 100081, China.

PMID: 32603081
DOI: 10.1021/acsami.0c04985

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.

Keywords: MoSe2; PbI2; Raman and PL spectroscopy; type II band alignment; vdW heterostructure.