Oxygen Vacancy Driven Sub-Band Gap Luminescence in Multilayer SnSe2/Graphene Heterostructures
Journal
ACS Applied Nano Materials
Journal Volume
9
Journal Issue
26
Start Page
12410
End Page
12421
ISSN
2574-0970
2574-0970
Date Issued
2026-06-18
Author(s)
Chen, Ding-Rui
Hung, Yuan-Chih
Wang, Tian-Hsin
Liu, Yuan-Yu
Lai, Peng-Yu
Ci, Ji-Wei
Wang, Ying-Yu
Chiu, Ching-Hsueh
Kang, Chen-Fang
He, Shih-Ming
Uen, Wu-Yih
Lan, Yann-Wen
Hsieh, Ya-Ping
Aoki, Nobuyuki
Kim, Gil-Ho
Hang, Da-Ren
Tsai, Dung-Sheng
Chuang, Chiashain
Abstract
The synergy between interfacial interactions and defect states in two-dimensional (2D) heterojunctions plays a critical role in determining their optoelectronic performances. Herein, we investigate the optoelectronic and charge transport properties of chemical vapor deposition-grown multilayer SnSe2/graphene heterostructures. Temperature-dependent photoluminescence (PL) and X-ray photoelectron spectroscopy reveal an anomalous, highly efficient visible-range sub-band gap luminescence in multilayer heterojunctions. Detailed analysis indicates that this phenomenon originates from environmental surface oxidation, where a thin SnOx interfacial layer introduces deep-level oxygen vacancy-induced defect states. These defect states effectively trap and pin photoexcited carriers, thereby competing with the steady-state temperature-dependent PL quenching process typically expected at the graphene Dirac point. Overall, this study clarifies the complex physical origins of defect-mediated radiative recombination in SnSe2 and provides critical insights into utilizing defect engineering to tailor the macroscopic optical and electrical performance of 2D heterostructures for next-generation optoelectronic and quantum devices.
Subjects
2D optoelectronics
interfacial charge transfer
oxygen-vacancy defects
SnSe2/graphene heterostructures
sub-band gap luminescence
Publisher
American Chemical Society (ACS)
Type
journal article