25,404 research outputs found
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 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
Location, Proximity, and M&A Transactions
In this paper, we examine how the geographic location of firms affects acquisition decisions and value creation for acquirers in takeover transactions. We find that firms located in an urban area are more likely to receive a takeover bid and complete a takeover transaction as a target than firms located in rural areas, and takeover deals involving an urban target are associated with higher acquirer announcement returns, after controlling for the proximity between the target and the acquirer. In addition, a target\u27s urban location significantly attenuates the negative effect of a long distance between the target and the acquirer on acquirer returns, a fact that is documented in the existing literature. Our findings reveal a previously underexplored force—firm location—that can affect takeover transactions, in addition to proximity. Our paper suggests that a firm\u27s location plays an important role in facilitating the dissemination of soft information and enhancing information-based synergies
Ozone Measurements with Meteors: A Revisit
Understanding the role of ozone in the Mesosphere/Lower Thermosphere (MLT)
region is essential for understanding the atmospheric processes in the upper
atmosphere. Earlier studies have shown that it is possible to use overdense
meteor trails to measure ozone concentration in the meteor region. Here we
revisit this topic by comparing a compilation of radar observations to
satellite measurements. We observe a modest agreement between the values
derived from these two methods, which confirm the usefulness of the meteor
trail technique for measuring ozone content at certain heights in the MLT
region. Future simultaneous measurements will help quantifying the performance
of this technique.Comment: MNRAS in pres
Multi-stability in an optomechanical system with two-component Bose-Einstein condensate
We investigate a system consisting of a two-component Bose-Einstein
condensate interacting dispersively with a Fabry-Perot optical cavity where the
two components of the condensate are resonantly coupled to each other by
another classical field. The key feature of this system is that the atomic
motional degrees of freedom and the internal pseudo-spin degrees of freedom are
coupled to the cavity field simultaneously, hence an effective spin-orbital
coupling within the condensate is induced by the cavity. The interplay among
the atomic center- of-mass motion, the atomic collective spin and the cavity
field leads to a strong nonlinearity, resulting in multi- stable behavior in
both matter wave and light wave at the few-photon level.Comment: 4 pages, 3 figure
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