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Biasing

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


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TL;DR: In this paper, the authors modeled the semiconductor as a resistor sandwiched between two identical head-to-head Schottky barriers and found that the voltage drop across the reverse-biased barrier is dominating at low bias voltage, and the dominant range depends on the value of the resistor.
Abstract: Symmetrical, non-linear and current–voltage (I–V) characteristics of a metal–semiconductor–metal (M-S-M) structure of two metallic Schottky contacts fabricated to a p-type semiconductor were modeled by treating the semiconductor as a resistor sandwiched between two identical head-to-head Schottky barriers. The voltage distributions along the M-S-M structure were numerically determined and found that the voltage drop across the reverse-biased Schottky barrier is dominating at the low bias voltage, and the dominant range depends on the value of the resistor of the semiconductor bulk. The field dependence of barrier height due to the image force was proposed to be the mechanism for the current through the M-S-M structure when the voltage drop across the reverse-biased barrier is dominating. The proposed model was applied to the I–V curves measured at different temperatures on low-resistivity p-type CdTe with Au contacts and the density of the effective acceptors calculated, and the zero-field Schottky barrier height and the Richardson constant were extracted using the activation energy method. The extracted parameters fitted well with that published for the same material structure.

54 citations

Journal ArticleDOI
TL;DR: In this paper, a composite preamplifier consisting of a slow dc amplifier in parallel with a fast ac amplifier is used to achieve high precision and high amplifier bandwidth of 50MHz.
Abstract: User-friendly ultra-high-speed readout electronics for dc superconducting quantum interference devices (SQUIDs) are presented. To maximize the system bandwidth, the SQUID is directly read out without flux modulation. A composite preamplifier is used consisting of a slow dc amplifier in parallel with a fast ac amplifier. In this way, excellent dc precision and a high amplifier bandwidth of 50 MHz are achieved, simultaneously. A virtual 50 Ω amplifier input resistance with negligible excess noise is realized by active shunting, i.e., by applying feedback from preamplifier output to input via a high resistance. The white voltage and current noise levels are 0.33 nV Hz−1 and 2.6 pA Hz−1/2, respectively. The electronics is fully computer controlled via a microcontroller integrated into the flux-locked loop (FLL) board. Easy-to-use software makes the various electronic settings accessible. A wide bias voltage range of 1.3 mV enables the readout of series SQUID arrays. Furthermore, additional current sources allow the operation of two-stage SQUIDs or transition edge sensors. The electronics was tested using various SQUIDs with input inductances between 30 nH and 1.5 µH. Typically, the maximum FLL bandwidth was 20 MHz, which is close to the theoretical limit given by transmission line delay within the FLL. Slew rates of up to 4.6 Φ0 µs−1 were achieved with series SQUID arrays. Current noise levels as low as 0.47 pA Hz−1/2 and coupled energy sensitivities between 90 h and 500 h were measured at 4.2 K, where h is the Planck constant. The noise did not degrade when the system bandwidth was increased to the maximum value of about 20 MHz. With a two-stage set-up, intrinsic white energy sensitivities of 30 h and 2.3 h were measured at 4.2 and 0.3 K, respectively.

54 citations

Journal ArticleDOI
TL;DR: In this paper, a graphene sheet gated with a ridged ground plane, creating a soft-boundary (SB) graphene nanoribbon, is considered and two types of modes are found; fundemental and higher-order modes with no apparent cutoff frequency and with energy distributed over the created channel, and edge modes with energy concen-trated at the softboundary edge.
Abstract: A graphene sheet gated with a ridged ground plane, creating a soft-boundary (SB) graphene nanoribbon, is considered. By adjusting the ridge parameters and bias voltage a channel can be created on the graphene which can guide TM surface plasmon polaritons (SPP). Two types of modes are found; fundemental and higher-order modes with no apparent cutoff frequency and with energy distributed over the created channel, and edge modes with energy concen-trated at the soft-boundary edge. Dispersion curves, electric near-field patterns, and current distributions of these modes are determined. Since the location where energy is concentrated in the edge modes can be easily controlled electronically by the bias voltage and frequency, the edge-mode phenomena is used to propose a novel voltage controlled plasmonic switch and a plasmonic frequency demultiplexer.

54 citations

Journal ArticleDOI
TL;DR: In this article, a polycrystalline ZnGa 2 Se 4 thin film was prepared by thermal evaporation technique on n-Si wafer followed by annealing at 700 K. The results show that the Al/p-ZnGa2 Se 4 /n-Si/Al heterojunction is a good candidate for the electronic device applications.

54 citations

Journal ArticleDOI
TL;DR: In this paper, a plasmonic structure consisting of multiple InGaAs/GaAs pseudomorphic high electron-mobility transistors connected in series was designed and tested for room temperature detection of terahertz radiation.
Abstract: We report on enhanced room-temperature detection of terahertz radiation by several connected field-effect transistors. For this enhanced nonresonant detection, we have designed, fabricated, and tested plasmonic structures consisting of multiple InGaAs/GaAs pseudomorphic high electron-mobility transistors connected in series. Results show a 1.63-THz response that is directly proportional to the number of detecting transistors biased by a direct drain current at the same gate-to-source bias voltages. The responsivity in the saturation regime was found to be 170 V/W with the noise equivalent power in the range of 10-7 W/Hz0.5. The experimental data are in agreement with the detection mechanism based on the rectification of overdamped plasma waves excited by terahertz radiation in the transistor channel.

54 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023256
2022488
2021480
2020923
2019946
2018977