Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userA Dual Gate Spin Field Effect Transistor With Very Low Switching Voltage and Large ON-to-OFF Conductance Ratio
106
0
0.0
(
0
)
Added by
Supriyo Bandyopadhyay
Publication date
2007
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
We propose and analyze a novel dual-gate Spin Field Effect Transistor (SpinFET) with half-metallic ferromagnetic source and drain contacts. The transistor has two gate pads that can be biased independently. It can be switched ON or OFF with a few mV change in the differential bias between the two pads, resulting in extremely low dynamic power dissipation during switching. The ratio of ON to OFF conductance remains fairly large (~ 60) up to a temperature of 10 K. This device also has excellent inverter characteristics, making it attractive for applications in low power and high density Boolean logic circuits.
rate research
Read More
A new azobenzene-thiophene molecular switch is designed, synthesized and used to form self-assembled monolayers (SAM) on gold. An on/off conductance ratio up to 7x1E3 (with an average value of 1.5x1E3) is reported. The on conductance state is clearly identified to the cis isomer of the azobenzene moiety. The high on/off ratio is explained in terms of photo-induced, configuration-related, changes in the electrode-molecule interface energetics (changes in the energy position of the molecular orbitals with respect to the Fermi energy of electrodes) in addition to changes in the tunnel barrier length (length of the molecules). First principles DFT calculations demonstrate a better delocalization of the frontier orbitals, as well as a stronger electronic coupling between the azobenzene moiety and the electrode for the cis configuration over the trans one. Measured photoionization cross-sections for the molecules in the SAM are close to the known values for azobenzene derivatives in solution.
Fundamental physical properties limiting the performance of spin field effect transistors are compared to those of ordinary (charge-based) field effect transistors. Instead of raising and lowering a barrier to current flow these spin transistors use static spin-selective barriers and gate control of spin relaxation. The different origins of transistor action lead to distinct size dependences of the power dissipation in these transistors and permit sufficiently small spin-based transistors to surpass the performance of charge-based transistors at room temperature or above. This includes lower threshold voltages, smaller gate capacitances, reduced gate switching energies and smaller source-drain leakage currents.
The fundamental property of most single-electron devices with quasicontinuous quasiparticle spectrum on the island is the periodicity of their transport characteristics in the gate voltage. This property is robust even with respect to placing the ferroelectric insulators in the source and drain tunnel junctions. We show that placing the ferroelectric inside the gate capacitance breaks this periodicity. The current-voltage characteristics of this SET strongly depends on the ferroelectric polarization and shows the giant memory-effect even for negligible ferroelectric hysteresis making this device promising for memory applications.
We study instability of plasmons in a dual-grating-gate graphene field-effect transistor induced by dc current injection using self-consistent simulations with the Boltzmann equation. With only the acoustic-phonon-limited electron scattering, it is demonstrated that a total growth rate of the plasmon instability, with the terahertz/mid-infrared range of the frequency, can exceed $4times10^{12}$ s$^{-1}$ at room temperature, which is an order of magnitude larger than in two-dimensional electron gases based on usual semiconductors. By Comparing the simulation results with existing theory, it is revealed that the giant total growth rate originates from simulataneous occurence of the so-called Dyakonov-Shur and Ryzhii-Satou-Shur instabilities.
We show that a Spin Field Effect Transistor, realized with a semiconductor quantum wire channel sandwiched between half-metallic ferromagnetic contacts, can have Fano resonances in the transmission spectrum. These resonances appear because the ferromagnets are half-metallic, so that the Fermi level can be placed above the majority but below the minority spin band. In that case, the majority spins will be propagating, but the minority spins will be evanescent. At low temperatures, the Fano resonances can be exploited to implement a digital binary switch that can be turned on or off with a very small gate voltage swing of few tens of microvolts, leading to extremely small dynamic power dissipation during switching. An array of 500,000 x 500,000 such transistors can detect ultrasmall changes in a magnetic field with a sensitivity of 1 femto-Tesla/sqrt{Hz}, if each transistor is biased near a Fano resonance.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
