Search results for "Field effect"
showing 10 items of 44 documents
Effect of temperature–bias annealing on the hysteresis and subthreshold behavior of multilayer MoS2 transistors
2016
The transfer characteristics (ID-VG) of multilayers MoS2 transistors with a SiO2/Si backgate and Ni source/drain contacts have been measured on as-prepared devices and after annealing at different temperatures (T-ann from 150 degrees C to 200 degrees C) under a positive bias ramp (V-G from 0 V to + 20 V). Larger T-ann resulted in a reduced hysteresis of the ID-VG curves (from similar to 11 V in the as-prepared sample to similar to 2.5 V after Tann at 200 degrees C). The field effect mobility (similar to 30 cm(2) V-1 s(-1)) remained almost unchanged after the annealing. On the contrary, the subthreshold characteristics changed from the common n-type behaviour in the as-prepared device to the…
CMOS-compatible field effect nanoscale gas-sensor: Operation and annealing models
2008
Complete modelling of electrically controlled nanoscale gas sensors with Poisson, Wolkenstein, Fokker-Planck and continuity is presented. Based on a plausible Drift explanation we developed suitable models for sensitivity control and operational modes. An onset for CMOS-complying annealing procedures is given.
High-Mobility Ambipolar Magnetotransport in Topological Insulator Bi2Se3 Nanoribbons
2021
Nanoribbons of topological insulators (TIs) have been suggested for a variety of applications exploiting the properties of the topologically protected surface Dirac states. In these proposals it is crucial to achieve a high tunability of the Fermi energy, through the Dirac point while preserving a high mobility of the involved carriers. Tunable transport in TI nanoribbons has been achieved by chemical doping of the materials so to reduce the bulk carriers' concentration, however at the expense of the mobility of the surface Dirac electrons, which is substantially reduced. Here we study bare ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ nanoribbons transferred on a variety of oxide substrates and dem…
The depolarization field effect on the thin ferroelectric films properties
2002
Abstract The calculation of the spontaneous polarization (Ps), dielectric susceptibility (χ) and pyroelectric coefficient (Π) of the ferroelectric films has been performed in the phenomenological theory framework. Euler–Lagrange equation was solved analytically under the boundary conditions with different extrapolation lengths at two surfaces, respectively. The depolarization field contribution was taken into account in the model of short-circuited mono domain ferroelectric film, treated as perfect insulator. The detailed analysis of the aforementioned quantities’ space distribution and their average values in two cases with and without depolarization field was carried out. It was shown tha…
Hysteresis in graphene nanoribbon field-effect devices
2020
Hysteresis in the current response to a varying gate voltage is a common spurious effect in carbon-based field effect transistors. Here, we use electric transport measurements to probe the charge transport in networks of armchair graphene nanoribbons with a width of either 5 or 9 carbon atoms, synthesized in a bottom-up approach using chemical vapor deposition. Our systematic study on the hysteresis of such graphene nanoribbon transistors, in conjunction with temperature-dependent transport measurements shows that the hysteresis can be fully accounted for by trapping/detrapping carriers in the SiO2 layer. We extract the trap densities and depth, allowing us to identify shallow traps as the …
Bright Beaches of Nanoscale Potassium Islands on Graphite in STM Imaging
2008
We demonstrate, via scanning tunneling microscopy (STM) measurements performed at 48 K, the existence of "bright beaches" at the edges of K islands (diameter approximately 5-500 nm) on the graphite surface. The enhanced tunneling current is only observed in monolayer-high islands on graphite, and not in islands of similar geometry on top of a K monolayer film. First-principles density functional calculations and STM simulations suggest that this is an STM field effect, which appears as the positive tip attracts donated electrons back to the metallic K islands. The restored charge accumulates preferentially at the island edges.
Magnetic field effect on electrodeposition of cobalt dendrites
2012
International audience; We are studying the effect of a magnetic field on cobalt dendrites grown by electrodeposition in thin cell. Several electrochemical parameters like pH, current density, initial concentration, are known to affect the crystalline structure of electrodeposited cobalt. Here we analyze, for two values of the pH, the effect of a high magnetic field (6 T) on the growth direction of the dendrites with respect to the crystalline axis of the structure.
Surface plasmon effects on carbon nanotube field effect transistors
2011
Herein, we experimentally demonstrate surface plasmon polariton (SPP) induced changes in the conductivity of a carbon nanotube field effect transistor (CNT FET). SPP excitation is done via Kretschmann configuration while the measured CNT FET is situated on the opposite side of the metal layer away from the laser, but within reach of the launched SPPs. We observe a shift of 0.4 V in effective gate voltage. SPP-intermediated desorption of physisorbed oxygen from the device is discussed as a likely explanation of the observed effect. This effect is visible even at low SPP intensities and within a near-infrared range. peerReviewed
Nanostructural depth-profile and field-effect properties of poly(alkoxyphenylene-thienylene) Langmuir-Schäfer thin-films
2008
The correlations between morphological features and field-effect properties of poly(alkoxyphenylene-thiophene) thin Langmuir–Schafer film deposited on differently terminated gate dielectric surfaces, namely bare and methyl functionalized thermal silicon dioxide (t-SiO2), have been systematically studied. The film morphology has been investigated at different film thickness by Scanning Force Microscopy. Films thicker than a few layers show comparable morphology on both dielectric surfaces while differences are seen for the ultra-thin polymer deposit in close proximity to the substrate. Such deposit is notably more heterogeneous on bare t-SiO2, while a more compact and uniform nanogranular st…
B7.3 - Field Effect SnO2 Nano-Thin Film Layer CMOS-Compatible
2009
The integration of metal oxide gas sensing layers into CMOS electronic still a challenge especially due to the high operating temperatures that do not comply with silicon transistor limits , even more critical, and metal oxide annealing temperatures. External electric fields will allow control over the energy levels of the sensing layer and thus over adsorption sensitivity, consequently the interaction between gas and sensitive layer is modulated. As the absorbed gas on the surface produces a band bending, it changes conduction paths allowing gas detection through resistance measurements. With this configuration, field switch offers fast desorption and thus handling of low temperature respo…