Raman intensity enhancement of molecules adsorbed onto HfS2 flakes up to 200 layers

Newly emerging two-dimensional transition metal dichalcogenide HfS2 has received considerable attention recently due to its ultrahigh photoresponsivity, well-balanced carrier mobility and an appropriate band gap which offer potential in electronic and optoelectronic devices. In this work, HfS2 flake...

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Bibliographic Details
Published in:Nanoscale 2019-02, Vol.11 (5), p.2179-2185
Main Authors: Xiao Fei Yue, Yao, Liang, Jiang, Jie, Liu, Rong Gang, Shou Tian Ren, Ren Xi Gao, Zhong, Bo, Guang Wu Wen, Wang, Ying Ying, Zou, Ming Qiang
Format: Article
Language:English
Subjects:
Absorption
Carrier mobility
Electronic devices
Energy gap
Flakes
Graphene
Hafnium compounds
Interference
Materials selection
Molybdenum disulfide
Monolayers
Multilayers
Optoelectronic devices
Raman spectra
Silicon dioxide
Silicon substrates
Stability
Transition metal compounds
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Summary:Newly emerging two-dimensional transition metal dichalcogenide HfS2 has received considerable attention recently due to its ultrahigh photoresponsivity, well-balanced carrier mobility and an appropriate band gap which offer potential in electronic and optoelectronic devices. In this work, HfS2 flakes up to 200 layers with varying color contrasts are fabricated and transferred on a SiO2/Si substrate. The Raman intensities of HfS2 flakes and Raman intensities of molecules adsorbed on HfS2 flakes are quantitatively studied both theoretically and experimentally by considering an optical interference effect. The effects of the main experimental factors: thickness of SiO2 and excitation wavelength on Raman intensities are also theoretically investigated. Due to the low absorption of HfS2, many strong high-order interference-induced enhancement peaks are observed which are different from high absorption materials like graphene and MoS2, in which only 2–4 interference-induced enhancement peaks exist. Due to the environmental instability of single layer HfS2 under ambient conditions, multi-layer HfS2 is a better choice than single layer HfS2 as a Raman scattering substrate which has a stronger Raman enhancement and a better environmental stability. The discovery here will expand the application of HfS2 flakes in molecular detection.
ISSN:2040-3364
2040-3372
DOI:10.1039/c8nr07185c