Plasma-Engineered Monolayer MoS<sub>2</sub> Films for Ultra-Sensitive Molecular Detection
Haoyang He, Fengrui Yang, Zhibin kuang, Maoshu Yang, Yuzhuo Yu, Wang Ai, Junjie Mao, Rui Shu, Yunfei Luo, Zhengwei Xie, Mingyang Tian, Jie Zheng, Mao Wang, Yijia Huang, Yarong Su, Luojun Du, Qinghua Zhang, Dehua Li, Zhichang Wang, Ling Li, Jianqi Zhu
Abstract
Recent surface-enhanced Raman spectroscopy (SERS) developments involve using nonmetallic materials as substrates. Molybdenum disulfide (MoS 2 ) is a notable nonmetal semiconductor surface-enhanced Raman scattering (SERS) substrate because of its low cost, abundance, remarkable stability, and considerable chemical activity. However, its limited SERS activity has significantly impeded its advancement in SERS research. Herein, we report a facile and efficient approach for rapidly producing monolayer MoS 2 films with adjustable sulfur vacancies via nitrogen plasma treatment. Monolayer MoS 2 films exhibit exceptional sensitivity for SERS detection by manipulating the vacancy density. The optimized MoS 2 substrate achieved a detection limit of roughly 10 –10 M and an enhancement factor of 2.29 × 10 5 for rhodamine 6G (R6G) probe molecules. We further illustrated that introducing sulfur vacancies can alter the bandgap structure of MoS 2, thereby facilitating the separation of internal charge carriers and intensifying interactions with the target components. The vacancy-assisted technique paves the path for the widespread use of semiconductor-based ultrasensitive molecular detection.