Search results for "conductor"
showing 10 items of 1270 documents
Earlier Developed Techniques
2014
The first electrochemical experiments were performed with solid materials, esp. metals. However, these experiments, conducted in the eighteenth and nineteenth centuries, were directed toward the elucidation of the basic features of the electrical action of chemical substances and the chemical action of electricity. Initially, metals played the major role; only later it became obvious that many chemical compounds possess metallic or semiconducting properties that can be utilized in electrochemical cells. Parallel to the studies of new electrode materials, solid electrolytes were discovered and entire solid galvanic cells could be constructed. In this book, we will entirely neglect pure solid…
Stimulated quasiparticles in spin-split superconductors
2015
Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).
Electromagnetic field fluctuations near a dielectric-vacuum boundary and surface divergences in the ideal conductor limit
2012
We consider the electric and magnetic field fluctuations in the vacuum state in the region external to a half-space filled with a homogeneous non-dissipative dielectric. We discuss an appropriate limit to an ideal metal and concentrate our interest on the renormalized field fluctuations, or equivalently to renormalized electric and magnetic energy densities, in the proximity of the dielectric-vacuum interface. We show that surface divergences of field fluctuations arise at the interface in an appropriate ideal conductor limit, and that our limiting procedure allows to discuss in detail their structure. Field fluctuations close to the surface can be investigated through the retarded Casimir-…
Comparative Determinations of Magnetic Induction in AC and DC Circuits
2019
The influence of the electromagnetic field on the human body, although still heavily studied, can have long-term negative effects. The static electromagnetic field is generated by a continuous current source and has a current flow characteristic conventionally set + from -. The variable electromagnetic field is produced by the alternating current and has the ability to change its direction over time with a frequency of 50 or 60 Hz. It is considered that the non-hazardous limit value for the magnetic field (according to Federal Office for Radiation Security in Germany) is 100 microT for 50 Hz and 83 microT for 60 Hz. For the electric field, the exposure limit value is 5kV/m. Electromagnetic …
Beam test results of IHEP-NDL Low Gain Avalanche Detectors(LGAD)
2020
A High-Granularity Timing Detector (HGTD) is proposed based on the Low-Gain Avalanche Detector (LGAD) for the ATLAS experiment to satisfy the time resolution requirement for the up-coming High Luminosity at LHC (HL-LHC). We report on beam test results for two proto-types LGADs (BV60 and BV170) developed for the HGTD. Such modules were manufactured by the Institute of High Energy Physics (IHEP) of Chinese Academy of Sciences (CAS) collaborated with Novel Device Laboratory (NDL) of the Beijing Normal University. The beam tests were performed with 5 GeV electron beam at DESY. The timing performance of the LGADs was compared to a trigger counter consisting of a quartz bar coupled to a SiPM read…
Gigahertz Single-Electron Pumping Mediated by Parasitic States
2018
In quantum metrology, semiconductor single-electron pumps are used to generate accurate electric currents with the ultimate goal of implementing the emerging quantum standard of the ampere. Pumps based on electrostatically defined tunable quantum dots (QDs) have thus far shown the most promising performance in combining fast and accurate charge transfer. However, at frequencies exceeding approximately 1 GHz, the accuracy typically decreases. Recently, hybrid pumps based on QDs coupled to trap states have led to increased transfer rates due to tighter electrostatic confinement. Here, we operate a hybrid electron pump in silicon obtained by coupling a QD to multiple parasitic states, and achi…
Residual strain effects on the two-dimensional electron gas concentration of AlGaN/GaN heterostructures
2001
Ga-face AlGaN/GaN heterostructures with different sheet carrier concentrations have been studied by photoluminescence and Raman spectroscopy. Compared to bulk GaN, an energy shift of the excitonic emission lines towards higher energies was observed, indicating the presence of residual compressive strain in the GaN layer. This strain was confirmed by the shift of the E2 Raman line, from which biaxial compressive stresses ranging between 0.34 and 1.7 GPa were deduced. The spontaneous and piezoelectric polarizations for each layer of the heterostructures have been also calculated. The analysis of these quantities clarified the influence of the residual stress on the sheet electron concentratio…
Measurement of drift mobilities in amorphous organic films using the Time of Flight method
2004
We apply the Time of Flight (TOF) technique to study carrier mobility in N, N’-diphenyl-N,N’-bis(3-methylphenyl) -1,1-biphenyl-4,4’-diamine (TPD) and tris(8-hydroxyquinolato) aluminium (Alq 3 ). These materials are two examples of, respectively, hole and electron transporting molecular materials. Measurements are performed in free air or under vacuum varying the experimental parameters such as laser pulse intensity and single shot irradiation. We observe a transition from dispersive to non dispersive transport changing the experimental conditions.
Location of holes in silicon-rich oxide as memory states
2002
The induced changes of the flatband voltage by the location of holes in a silicon-rich oxide (SRO) film sandwiched between two thin SiO 2 layers [used as gate dielectric in a metal-oxide-semiconductor (MOS) capacitor] can be used as the two states of a memory cell. The principle of operation is based on holes permanently trapped in the SRO layer and reversibly moved up and down, close to the metal and the semiconductor, in order to obtain the two logic states of the memory. The concept has been verified by suitable experiments on MOS structures. The device exhibits an excellent endurance behavior and, due to the low mobility of the holes at low field in the SRO layer, a much longer refresh …
Tin-related double acceptors in gallium selenide single crystals
1998
Gallium selenide single crystals doped with different amounts of tin are studied through resistivity and Hall effect measurements in the temperature range from 30 to 700 K. At low doping concentration tin is shown to behave as a double acceptor impurity in gallium selenide with ionization energies of 155 and 310 meV. At higher doping concentration tin also introduces deep donor levels, but the material remains p-type in the whole studied range of tin doping concentrations. The deep character of donors in gallium selenide is discussed by comparison of its conduction band structure to that of indium selenide under pressure. The double acceptor center is proposed to be a tin atom in interlayer…