Biasing

About: Biasing is a research topic. Over the lifetime, 29422 publications have been published within this topic receiving 301035 citations.

Hydrogen and hydrocarbon gas sensing performance of Pt/WO3/SiC MROSiC devices

Abstract: Pt/WO3/SiC devices based Schottky diodes have been fabricated and their hydrogen and hydrocarbon gas sensing performance investigated. The semiconducting metal oxide WO3 films were 100 nm thick and prepared using r.f. magnetron sputtering. A Pt layer was deposited on the top of the WO3 forming the Schottky diode. The I–V characteristics have been analyzed, from which the change in the barrier height, subject to the introduction of the analyte gas, was calculated. The dynamic properties of these sensors were evaluated at constant biasing currents of 9 and 90 μA, at temperatures between 300 and 700 °C. The results show the sensors have extremely stable baseline, with all responses being repeatable. Voltages shifts in excess of 1 V were observed.

Microwave phenomena in bulk GaAs

Abstract: CW microwave oscillations were generated at room temperature by using n -GaAs with a carrier concentration 1013- 1014per cc. Fundamental frequencies between 1 - 10 kMc were excited, and harmonic signals up to 21 kMc were detected. The maximum power output and efficiency on CW basis were 56 mW and 5.2 percent, respectively, at 2 - 3 kMc. A study was made of harmonic content, linewidth, circuit and electronic tunability, as well as the effects of sample thickness, bias voltage, and temperature, on the observed signal frequency. For sample length × carrier concentration products between 2×1010- 2 × 1012cm-2there was a wide diversity in behavior observed in different samples. This was tentatively attributed to the possibility of exciting not only traveling dipole domains but also growing space-charge waves. These growing space-charge waves were found to exist in samples where the condition nl < 2 × 1012cm-2was satisfied, and are also suspected of being responsible for the observed microwave amplification in bulk GaAs. Three different contacts were used successfully: nickeltin, indium-nickel, and indium-gold. These contacts, and the general semiconductor preparation techniques, will be described in detail.

Noise properties of ferromagnetic tunnel junctions

Abstract: We report measurements of voltage fluctuations in magnetic tunnel junctions which exhibit both high and low magnetoresistance (MR). The voltage noise power normalized to the square of the junction bias voltage was 10−14/Hz at a frequency of 1 Hz in a high MR junction. Low MR junctions had significantly higher noise power at 1 Hz and the origin of the noise was not magnetic. In these junctions, random telegraph noise was observed over a wide range of temperatures and junction biases. The results are consistent with a two-channel model of conduction, one of which is spin independent and gives rise to large noise. A noise measuring technique provides evidence for bias-dependent current-path rearrangements. The data support the existence of an inhomogeneous (filamentary-like) current-flow pattern across the tunnel junction associated with the spin-independent channel.

Coulomb staircases and quantum size effects in tunnelling spectroscopy on ligand-stabilized metal clusters

Abstract: We describe scanning tunnelling spectroscopy results on the ligand-stabilized metal cluster Pt309Phen36*O30 (where Phen is phenanthrolin) at 4.2 K. If the STM tip is positioned above a single cluster, clear charging effects are observed, varying from a reduction of the current around zero bias (Coulomb blockade) to a stepwise increase of the current as a function of bias voltage (Coulomb staircase). In addition to the regular Coulomb staircase with steps in the current at equal voltage spacing, we observed also staircases whit additional structure. This additional structure can be explained in terms of quantum levels in the cluster.

Driver and method of operating a micro-electromechanical system device

Abstract: A driver for use with a micro-electromechanical system (MEMS) device, method of operation thereof and a MEMS device employing the driver and method. In one embodiment, the driver includes an actuation subsystem that provides an actuation voltage to alter an angle of an optical element of the MEMS device. The driver also includes a bias subsystem, coupled to the actuation subsystem, that applies a bias voltage between the optical element and the actuation subsystem, thereby reducing the actuation voltage.