Effect of Substrate on Sulfur Vacancy Defect-Mediated Photoluminescence in Two-Dimensional MoS 2

Journal article

Chalcogen vacancy defects in monolayer transition metal dichalcogenides form in-gap states that can trap excitons, leading to defect-mediated photoluminescence (PL) emission. Here, we show that room-temperature (RT, 300 K) PL from sulfur vacancies in defective monolayer MoS2 is sensitive to doping from dielectric substrates such as SiO2 and HfO2. The defect-mediated PL is observed for monolayer MoS2 on untreated HfO2 but is quenched on untreated SiO2, which is attributed to electron doping of MoS2 on SiO2. Electron doping of MoS2 is confirmed by Raman and synchrotron X-ray photoelectron spectroscopy. Annealing of the SiO2 substrate modifies its surface states, which is reflected in the recovery of the defect-mediated PL emission. The role of substrate-induced doping on sulfur vacancy-mediated PL is further supported by gate-dependent PL measurements. Our results suggest that excess electrons fill the defect energy states from sulfur vacancies in MoS2, reducing the probability of photoexcited carrier occupation and subsequent defect-mediated emission.

Authors: Zhu, Y; Zhang, Z; Wang, Y; Sarkar, S; Li, Y

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: The Journal of Physical Chemistry C
• Volume: 129
• Issue: 17
• Pages: 8294-8302
• Publication date: 2025-04-18
• Acceptance date: 2025-04-03
• DOI: 10.1021/acs.jpcc.4c08491
• EISSN: 1932-7455
• ISSN: 1932-7447
• Language: English