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Probing the Electronic Properties of Monolayer MoS <sub/>2</sub> via Interaction with Molecular Hydrogen
摘要： This work presents a detailed experimental investigation of the interaction between molecular hydrogen (H2) and monolayer MoS2 field effect transistors (MoS2 FET), aiming for sensing application. The MoS2 FET exhibits a response to H2 that covers a broad range of concentration (0.1–90%) at a relatively low operating temperature range (300–473 K). Most important, H2 sensors based on MoS2 FETs show desirable properties such as full reversibility and absence of catalytic metal dopants (Pt or Pd). The experimental results indicate that the conductivity of MoS2 monotonically increases as a function of the H2 concentration due to a reversible charge transferring process. It is proposed that such process involves dissociative H2 adsorption driven by interaction with sulfur vacancies in the MoS2 surface (VS). This description is in agreement with related density functional theory studies about H2 adsorption on MoS2. Finally, measurements on partially defect-passivated MoS2 FETs using atomic layer deposited aluminum oxide consist of an experimental indication that the VS plays an important role in the H2 interaction with the MoS2. These findings provide insights for future applications in catalytic process between monolayer MoS2 and H2 and also introduce MoS2 FETs as promising H2 sensors.
关键词： hydrogen gas sensor,gas interaction,hydrogen detection,monolayer MoS2,field effect transistors
更新于2025-09-10 09:29:36
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Temperature dependence of the dielectric function of monolayer MoS2
摘要： An analytic expression of the dielectric function of monolayer molybdenum disulfide (MoS2) ε = ε1 + iε2 is presented for energies from 1.4 to 6.0 eV and temperatures from 35 to 350 K. The dielectric function parametric model is used to express ε as a sum of polynomials, which naturally includes asymmetry of critical-point lineshapes. The temperature dependence is achieved by fitting model parameters. In this way the dielectric function of MoS2 for arbitrary temperature can be calculated. We observed the fundamental absorption peak, which occurs at the K point of the Brillouin zone. These results are expected to be useful in designing and understanding applied-device technologies based on monolayer MoS2.
关键词： Monolayer MoS2,Ellipsometry,Dielectric function parametric model,Dielectric function
更新于2025-09-10 09:29:36
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Performance analysis of a substrate-engineered monolayer MoS2 field-effect transistor
摘要： We investigate the impact of different substrates on the performance of a monolayer MoS2 field-effect transistor (FET) by calculating the interface charge density between the MoS2 layer and the substrate using first-principle calculations based on density functional theory to provide details about the overlap of electron orbitals at the interface. The electrical characteristics of the monolayer MoS2 FET are determined by using the extracted interface charge density in numerical simulations. The electron transport behavior of the monolayer MoS2 FET is modeled using the nonequilibrium Green’s function with mode space (NEGF_MS) approach. We study and compare the performance of monolayer MoS2 FETs on different substrates, viz. SiO2, HfSiO4, Si3N4, HfO2, and h-BN. The results reveal that the monolayer MoS2 FET on the h-BN/Si substrate exhibits an on-current of 548 μA/μm and a subthreshold swing of 65 mV/dec.
关键词： Carrier fluctuations,Electron transport,Charge density,NEGF_MS,Monolayer MoS2 FET
更新于2025-09-09 09:28:46
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Large enhancement of infrared absorption due to trimer comprised of doping-N and S-S divacancies in the imperfect monolayer MoS2: A first-principles study
摘要： In this study, we systematically study on crystal and electronic structures and optical absorption properties of perfect monolayer MoS2 (M), M with S vacancy (M@SV), M with N doping at S site (M@ND) and M with both S vacancy and N doping at S site (M@V-D) using first-principles method. It is showed that the N atom is tend to located between Mo and S layers, leaving one vacancy at original site, to form interstitial N atom. Thus, the interstitial N atom and the S vacancy make up the NI-VS dimer. We study M@V-D with five atomic configurations and find the most stable structure having the NI-VS-VS trimer. It is showed that the absorbance for the stable M@V-D in the most infrared region is obviously higher than that for the other systems. It is revealed that large enhancement of infrared absorption for the stable M@V-D is mainly attributable to the special electronic structure determined by the crystal structure with the trimer. It is considered that M@V-D could be the promising candidate for infrared materials.
关键词： Monolayer MoS2,Infrared absorption
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Perfect Absorber Based on Monolayer MoS2 and Nano-Silver in the Visible Regime
摘要： The monolayer MoS2 offer wide band gap and has great potential in energy storage, sensor, photonics. In this paper, we design and simulate a perfect absorber based on the local surface plasmon resonance and the coupling properties between the Ag pattern and the monolayer MoS2. The absorption value is almost 100% at peak, and the bandwidth of the absorption greater than 90% can reach 20THz. It is also polarization independent due to the fourfold rotational structural symmetry. The absorption value still remains over 90% when the incident angle increases to 60 degrees. The absorber has a great potential in many applications such as photodetectors, solar cell, sensors.
关键词： monolayer MoS2,coupling,absorber,nano-Ag,broad-angle
更新于2025-09-04 15:30:14