atmospheric-pressure-fabrication-large-sized-single-layer-rectangular

Atmospheric Pressure Fabrication of Large-Sized Single-Layer Rectangular SnSe Flakes

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for ...

Shenzhen University

National University of Singapore

Shenzhen university

Surface-enhanced Raman scattering (SERS) substrates with high activity and stability are desirable for SERS sensing. Here, we report a new single atomic layer graphitic-CN(S-g-CN) and Ag nanoparticles (NPs) hybrid as high-performance SERS substrates. The SERS mechanism of the highly stable S-g-CN/Ag substrates was systematically investigated by a combination of experiments and theoretical calculations. From the results of XPS and Raman spectroscopies, it was found that there was a strong interaction between S-g-CNand Ag NPs, which facilitates the uniform distribution of Ag NPs over the edges and surfaces of S-g-CNnanosheets, and induces a charge transfer from S-g-CNto the oxidizing agent through the silver surface, ultimately protecting Ag NPs from oxidation. Based on the theoretical calculations, we found that the net surface charge of the Ag atoms on the S-g-CN/Ag substrates was positive and the Ag NPs presented high dispersibility, suggesting that the Ag atoms on the S-g-CN/Ag substrates were not likely to be oxidized, thereby ensuring the high stability of the S-g-CN/Ag substrate. An understanding of the stability mechanism in this system can be helpful for developing other effective SERS substrates with long-term stability.

Use of Single-Layer g-CN/Ag Hybrids for Surface-Enhanced Raman Scattering (SERS).

Monolayer two-dimensional (2D) transition metal dichalcogenides (TMDs) show interesting optical and electrical properties because of their direct bandgap. However, the low absorption of atomically thin TMDs limits their applications. Here, we report enhanced absorption and optoelectronic properties of monolayer molybdenum disulfide (MoS) by using an asymmetric Fabry-Perot cavity. The cavity is based on a hybrid structure of MoS/ hexagonal boron nitride (BN)/Au/SiOrealized through layer-by-layer vertical stacking. Photoluminescence (PL) intensity of monolayer MoSis enhanced over 2 orders of magnitude. Theoretical calculations show that the strong absorption of MoScomes from photonic localization on the top of the microcavity at optimal BN spacer thickness. The n/nMoShomojunction photodiode incorporating this asymmetric Fabry-Perot cavity exhibits excellent current rectifying behavior with an ideality factor of 1 and an ultrasensitive and gate-tunable external photo gain and specific detectivity. Our work offers an effective method to achieve uniform enhanced light absorption by monolayer TMDs, which has promising applications for highly sensitive optoelectronic devices.

Article	Year
Use of Single-Layer g-CN/Ag Hybrids for Surface-Enhanced Raman Scattering (SERS). Scientific reports\| PubMed ID: 27687573	2016
Fabry-Perot Cavity-Enhanced Optical Absorption in Ultrasensitive Tunable Photodiodes Based on Hybrid 2D Materials. Nano letters\| PubMed ID: 29115838	2017

Jizhou Jiang

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