2,518 research outputs found
Gate-controlled reversible rectifying behaviour in tunnel contacted atomically-thin MoS transistor
Atomically-thin 2D semiconducting materials integrated into van der Waals
heterostructures have enabled architectures that hold great promise for next
generation nanoelectronics. However, challenges still remain to enable their
full acceptance as compliant materials for integration in logic devices. Two
key-components to master are the barriers at metal/semiconductor interfaces and
the mobility of the semiconducting channel, which endow the building-blocks of
diode and field effect transistor. Here, we have devised a reverted
stacking technique to intercalate a wrinkle-free h-BN tunnel layer between
MoS channel and contacting electrodes. Vertical tunnelling of electrons
therefore makes it possible to suppress the Schottky barriers and Fermi level
pinning, leading to homogeneous gate-control of the channel chemical potential
across the bandgap edges. The observed unprecedented features of ambipolar
to diode, which can be reversibly gate tuned, paves the way for
future logic applications and high performance switches based on atomically
thin semiconducting channel.Comment: 23 pages, 5 main figures + 9 SI figure
Vertical Field-Effect Transistor Based on Wavefunction Extension
We demonstrate a mechanism for a dual layer, vertical field-effect
transistor, in which nearly-depleting one layer will extend its wavefunction to
overlap the other layer and increase tunnel current. We characterize this
effect in a specially designed GaAs/AlGaAs device, observing a tunnel current
increase of two orders of magnitude at cryogenic temperatures, and we suggest
extrapolations of the design to other material systems such as graphene
Low-dimensional light-emitting transistor with tunable recombination zone
We present experimental and numerical studies of a light-emitting transistor
comprising two quasi-lateral junctions between a two-dimensional electron and
hole gas. These lithographically defined junctions are fabricated by etching of
a modulation doped GaAs/AlGaAs heterostructure. In this device electrons and
holes can be directed to the same area by drain and gate voltages, defining a
recombination zone tunable in size and position. It could therefore provide an
architecture for probing low-dimensional devices by analysing the emitted light
of the recombination zone.Comment: 12 Pages, to be published in Journal of Modern Optic
Low disordered, stable, and shallow germanium quantum wells: a playground for spin and hybrid quantum technology
Buried-channel semiconductor heterostructures are an archetype material
platform to fabricate gated semiconductor quantum devices. Sharp confinement
potential is obtained by positioning the channel near the surface, however
nearby surface states degrade the electrical properties of the starting
material. In this paper we demonstrate a two-dimensional hole gas of high
mobility ( cm/Vs) in a very shallow strained germanium
channel, which is located only 22 nm below the surface. This high mobility
leads to mean free paths , setting new benchmarks for holes in
shallow FET devices. Carriers are confined in an undoped Ge/SiGe
heterostructure with reduced background contamination, sharp interfaces, and
high uniformity. The top-gate of a dopant-less field effect transistor controls
the carrier density in the channel. The high mobility, along with a percolation
density of , light effective mass (0.09
m), and high g-factor (up to ) highlight the potential of undoped
Ge/SiGe as a low-disorder material platform for hybrid quantum technologies
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