Type-II Interface Band Alignment in the vdW PbI2-MoSe2 Heterostructure.
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.
['Xiao|Junting|J|', 'Zhang|Lei|L|', 'Zhou|Hui|H|', 'Shao|Ziyi|Z|', 'Liu|Jinxin|J|', 'Zhao|Yuan|Y|', 'Li|Youzhen|Y|http://orcid.org/0000-0001-8994-3627', 'Liu|Xiaoliang|X|', 'Xie|Haipeng|H|', 'Gao|Yongli|Y|', 'Sun|Jia-Tao|JT|', 'Wee|Andrew T S|ATS|http://orcid.org/0000-0002-5828-4312', 'Huang|Han|H|http://orcid.org/0000-0003-0641-1962']
PbI2 MoSe2 Raman and PL spectroscopy type II band alignment vdW heterostructure