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Physics Seminar - Pengfei Yang and Yanfeng Zhang

Wednesday, 4 December 2019

Physics Department

Pengfei Yang and Yanfeng Zhang

PhD Student

Peking University, Beijing

"Wafer-scale production of monolayer and few-layer molybdenum disulphide films"

Atomically thin transition metal dichalcogenides (TMDCs) have received substantial interests due to their unique thickness-dependent optical and electronic properties, and related applications in optoelectronics. However, the large-scale, thickness-tunable growth of such materials are still challenging. Herein, we report a fast growth of 6-inch scale, thickness tunable MoS2 flakes on common soda-lime glass, through a designed “face-to-face” metal-precursor supply route in a facile chemical vapour deposition process. We find that, for the highly uniform monolayer film, with the composite domains possessing edge length of ~400 µm, can be achieved within a quite short time of ~8 min. This highly efficient growth is proved to be facilitated by Na catalysts that homogenously distributed on glass surfaces, according to our experimental facts and DFT calculations. Moreover, the MoS2 thicknesses are tuned from one layer (1L) to ˃20L by controlling the concentrations of NaCl promoter. To attest the ultrahigh crystal quality, related devices based on monolayer−multilayer MoS2 heterojunctions have been constructed and displayed relative high rectification ratio (~103) and extra high photoresponsitivity (~104 A/W). Thanks to the scalable sizes, the applications in bio-compatible culture plates and ultraviolet (UV) irradiation filtering eyewear are also demonstrated. Our work should hereby propel the scalable production of layer-controlled TMDCs, as well as their optical and optoelectrical applications. Reference 1. Yang, P., Liu, Z., Zhang, Y.*, et al. Nat. Commun. 2018, 9, 1 2. Yang, P., Liu, Z., Zhang, Y.*, et al. ACS Nano 2019, 13, 3649

WHEN: Wednesday 54 December 2019
WHERE: Room 314, Science 3 Building
TIME: 3.00 pm–4.00 pm

All interested are welcome to attend

Light refreshments to follow in Common Room