Search results for "INSULATOR"
showing 10 items of 228 documents
Thermal characteristics of silicon nitride membranes at sub-Kelvin temperatures
1998
We have performed calorimetric measurements on 200 nm thin silicon nitride membranes at temperatures from 0.07 to 1 K. Besides full windows, membranes cut into a thermally isolating suspended bridge geometry were investigated. Based on dc and ac measurements employing normal-metal/insulator/superconductor (NIS) tunnel junctions both as a thermometer and a heater, we report on heat transport and thermal relaxation in silicon nitride films. The bridge structure improves thermal isolation and, consequently, energy sensitivity by two orders of magnitude over those of the full membrane with the same size, and makes such a structure very attractive for bolometric and microrefrigeration applicatio…
Memory effects in MOS capacitors with silicon quantum dots
2001
To form crystalline Si dots embedded in SiO2, we have deposited thin films of silicon-rich oxide (SRO) by plasma-enhanced chemical vapor deposition of SiH4 and O2. Then the materials have been annealed in N2 ambient at temperatures between 950°C and 1100°C. Under such processing, the supersaturation of Si in the amorphous SRO film produces the formation of crystalline Si dots embedded in SiO2. The narrow dot size distributions, analyzed by transmission electron microscopy, are characterized by average grain radii and standard deviations down to about 1 nm. The memory functions of such structures has been investigated in MOS capacitors with a SRO film sandwiched between two thin SiO2 layers …
Silicon quantum point contact with aluminum gate
2000
Fabrication and electrical properties of silicon quantum point contacts are reported. The devices are fabricated on bonded silicon on insulator (SOI) wafers by combining CMOS process steps and e-beam lithography. Mobility of 9000 cm2 Vs−1 is measured for a 60 nm-thick SOI film at 10 K. Weak localization data is used to estimate the phase coherence length at 4.2 K The point contacts show step like behaviour in linear response conductance at 1.5 K. At 200 mK universal conductance fluctuations begin to dominate the conductance curve. The effective diameter of quantum point constrictions of the devices are estimated to be 30–40 nm. This estimate is based on TEM analysis of test structures and A…
Electron-phonon heat transport and electronic thermal conductivity in heavily doped silicon-on-insulator film
2003
Electron–phonon interaction and electronic thermal conductivity have been investigated in heavily doped silicon at subKelvin temperatures. The heat flow between electron and phonon systems is found to be proportional to T6. Utilization of a superconductor–semiconductor–superconductor thermometer enables a precise measurement of electron and substrate temperatures. The electronic thermal conductivity is consistent with the Wiedemann–Franz law. Peer reviewed
10 Gb/s transmission and thermo-optic resonance tuning in silicon-plasmonic waveguide platform
2011
The first system-level experimental results of hybrid Si-DLSPP structures incorporated into a SOI chip are reported. We demonstrate over 7nm thermo-optical tuning of a Si-Plasmonic racetrack-resonator and verify error-free 10Gb/s transmission through 60um Si-Plasmonic waveguide.
Silicon Single Electron Transistors with Single and Multi Dot Characteristics
2000
AbstractSilicon single electron transistors (SET) with side gate have been fabricated on a heavily doped silicon-on-insulator (SOI) substrate. Samples demonstrate two types of characteristics: some of them demonstrate multiple dot behavior and one demonstrates single dot behavior in a wide temperature range. SETs demonstrate oscillations of drain-source current and changes in the width of the Coulomb blockade region with change of gate voltage at least up to 100 K. At temperature below 20 K long-term oscillations (relaxation) of source-drain current after switching the gate voltage has been observed in both multiple dot and single dot samples. Illumination affects both the characteristics o…
Single electron transistor fabricated on heavily doped silicon-on-insulator substrate
2001
Experiments on side-gated silicon single electron transistors (SET) fabricated on a heavily doped thin silicon-on-insulator substrate are reported. Some of the devices showed single-island-like and some multi-island-like behaviour, but the properties of individual samples changed with time. Single-electron gate modulation was observable up to T=100 K, at least. A slow response of SET current to a large change in gate voltage was observed, but the process speeded up under illumination.
Atomistic Theory of the Growth Mode for a Thin Metallic Film on an Isulating Substrate
2002
We have developed a novel theory for predicting the growth mode of a thin metallic film on an insulating substrate. Our theory combines ab initio electronic structure calculations for several ordered metal/insulator interfaces with varying metal coverage, with a thermodynamic method known in the theory of alloys. We illustrate this approach for an Ag film deposited on a MgO(001) substrate. Ab initio Hartree-Fock calculations predict a high mobility of adsorbed silver atoms on the perfect magnesia surface even at low temperatures. Our theoretical analysis clearly demonstrates that the growth of metal islands is predominant at the initial stage of silver deposition on MgO, which agrees with t…
Giant Edelstein effect in Topological-Insulator--Graphene heterostructures
2017
The control of a ferromagnet's magnetization via only electric currents requires the efficient generation of current-driven spin-torques. In magnetic structures based on topological insulators (TIs) current-induced spin-orbit torques can be generated. Here we show that the addition of graphene, or bilayer graphene, to a TI-based magnetic structure greatly enhances the current-induced spin density accumulation and significantly reduces the amount of power dissipated. We find that this enhancement can be as high as a factor of 100, giving rise to a giant Edelstein effect. Such a large enhancement is due to the high mobility of graphene (bilayer graphene) and to the fact that the graphene (bil…
Emergence of a metallic metastable phase induced by electrical current in Ca2RuO4
2019
A comprehensive study of the behavior of the Mott insulator ${\mathrm{Ca}}_{2}{\mathrm{RuO}}_{4}$ under electrical current drive is performed by combining two experimental probes: the macroscopic electrical transport and the microscopic x-ray diffraction. The resistivity, $\ensuremath{\rho}$, versus electric current density, $J$, and temperature, $T,\ensuremath{\rho}(J,T)$, resistivity map is drawn. In particular, the metastable state, induced between the insulating and the metallic thermodynamic states by current biasing ${\mathrm{Ca}}_{2}{\mathrm{RuO}}_{4}$ single crystals, is investigated. Such an analysis, combined with the study of the resulting ${\mathrm{RuO}}_{6}$ octahedra energy le…