135 research outputs found
MoS2 Dual-Gate MOSFET with Atomic-Layer-Deposited Al2O3 as Top-Gate Dielectric
We demonstrate atomic-layer-deposited (ALD) high-k dielectric integration on
two-dimensional (2D) layer-structured molybdenum disulfide (MoS2) crystals and
MoS2 dual-gate n-channel MOSFETs with ALD Al2O3 as top-gate dielectric. Our C-V
study of MOSFET structures shows good interface between 2D MoS2 crystal and ALD
Al2O3. Maximum drain currents using back-gates and top-gates are measured to be
7.07mA/mm and 6.42mA/mm at Vds=2V with a channel width of 3 {\mu}m, a channel
length of 9 {\mu}m, and a top-gate length of 3 {\mu}m. We achieve the highest
field-effect mobility of electrons using back-gate control to be 517 cm^2/Vs.
The highest current on/off ratio is over 10^8.Comment: submitted to IEEE Electron Device Letter
Atomic-Layer-Deposited Al2O3 on Bi2Te3 for Topological Insulator Field-Effect Transistors
We report dual-gate modulation of topological insulator field-effect
transistors (TI FETs) made on Bi2Te3 thin flakes with integration of
atomic-layer-deposited (ALD) Al2O3 high-k dielectric. Atomic force microscopy
study shows that ALD Al2O3 is uniformly grown on this layer-structured channel
material. Electrical characterization reveals that the right selection of ALD
precursors and the related surface chemistry play a critical role in device
performance of Bi2Te3 based TI FETs. We realize both top-gate and bottom-gate
control on these devices, and the highest modulation rate of 76.1% is achieved
by using simultaneous dual gate control.Comment: 4 pages, 3 figure
MoS2 Nanoribbon Transistors: Transition from Depletion-mode to Enhancement-mode by Channel Width Trimming
We study the channel width scaling of back-gated MoS2
metal-oxide-semiconductor field-effect transistors (MOSFETs) from 2 {\mu}m down
to 60 nm. We reveal that the channel conductance scales linearly with channel
width, indicating no evident edge damage for MoS2 nanoribbons with widths down
to 60 nm as defined by plasma dry etching. However, these transistors show a
strong positive threshold voltage (VT) shift with narrow channel widths of less
than 200 nm. Our results also show that transistors with thinner channel
thicknesses have larger VT shifts associated with width scaling. Devices
fabricated on a 6 nm thick MoS2 crystal underwent the transition from
depletion-mode to enhancement-mode.Comment: 3 pages, 3 figures, to appear in IEEE Electron Device Letter
Magneto-Transport in MoS2: Phase Coherence, Spin Orbit Scattering and the Hall Factor
We have characterized phase coherence length, spin orbit scattering length,
and the Hall factor in n-type MoS2 2D crystals via weak localization
measurements and Hall-effect measurements. Weak localization measurements
reveal a phase coherence length of ~50 nm at T = 400 mK for a few-layer MoS2
film, decreasing as T^-1/2 with increased temperatures. Weak localization
measurements also allow us, for the first time without optical techniques, to
estimate the spin orbit scattering length to be 430 nm, pointing to the
potential of MoS2 for spintronics applications. Via Hall-effect measurements,
we observe a low temperature Hall mobility of 311 cm2/Vs at T = 1 K which
decreases as a power law with a characteristic exponent {\gamma}=1.5 from 10 K
to 60 K. At room temperature, we observe Hall mobility of 24 cm2/Vs. By
determining the Hall factor for MoS2 to be 1.35 at T = 1 K and 2.4 at room
temperature, we observe drift mobility of 420 cm2/Vs and 56 cm2/Vs at T = 1 K
and room temperature, respectively.Comment: ACS Nano nn402377
High-performance field effect transistors with self-assembled nanodielectrics
Field effect transistor devices comprising III-V semiconductors and organic gate dielectric materials, such dielectric materials as can afford flexibility in device design and fabrication
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