2,519 research outputs found
Gas Sensing with h-BN Capped MoS2 Heterostructure Thin Film Transistors
We have demonstrated selective gas sensing with molybdenum disulfide (MoS2)
thin films transistors capped with a thin layer of hexagonal boron nitride
(h-BN). The resistance change was used as a sensing parameter to detect
chemical vapors such as ethanol, acetonitrile, toluene, chloroform and
methanol. It was found that h-BN dielectric passivation layer does not prevent
gas detection via changes in the source-drain current in the active MoS2 thin
film channel. The use of h-BN cap layers (thickness H=10 nm) in the design of
MoS2 thin film gas sensors improves device stability and prevents device
degradation due to environmental and chemical exposure. The obtained results
are important for applications of van der Waals materials in chemical and
biological sensing.Comment: 3 pages; 4 figure
Low-noise top-gate graphene transistors
We report results of experimental investigation of the low-frequency noise in
the top-gate graphene transistors. The back-gate graphene devices were modified
via addition of the top gate separated by 20 nm of HfO2 from the single-layer
graphene channels. The measurements revealed low flicker noise levels with the
normalized noise spectral density close to 1/f (f is the frequency) and Hooge
parameter below 2 x 10^-3. The analysis of the noise spectral density
dependence on the top and bottom gate biases helped us to elucidate the noise
sources in these devices and develop a strategy for the electronic noise
reduction. The obtained results are important for all proposed graphene
applications in electronics and sensors.Comment: 9 pages, 4 figure
Terahertz Response of Field-Effect Transistors in Saturation Regime
We report on the broadband THz response of InGaAs/GaAs HEMTs operating at
1.63 THz and room temperature deep in the saturation regime. We demonstrate
that responses show linear increase with drain-to-source voltage (or drain bias
current) and reach very high values up to 170V/W. We also develop a
phenomenological theory valid both in the ohmic and in the saturation regimes.Comment: 11 pages, 3 figure
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