2,659 research outputs found
Highly sensitive InGaAs=InAlAs quantum wire photo-FET
An InGaAs=InAlAs quantum wire photo-FET has been fabricated on a V-grooved (311) InP substrate by atomic hydrogen assisted molecular beam epitaxy. The room-temperature photosensitivity of the quantum wire photo-FET reached 350 kA=W near a wavelength of 700 nm at a drain-source voltage of 1 V. Introduction: The pin diode is the simplest of the commercially available photodetectors in terms of device structure and is suitable for application to a detector array. However, its sensitivity is limited to about 1 A=W, which is the quantum efficiency of the photo-absorption material. In such a case, the detection limit is determined by the additional electronic noise induced by the current amplifier. In contrast, an avalanche photodiode (APD) and a photo-multiplier (PMT) have higher sensitivity because of their amplification mechanism, but they are not very suitable for multi-pixel arrays because of their inferior uniformity and higher bias voltage. The bias voltages of an APD (1 kV) may easily damage a silicon charge amplifier within the same package if the element breaks down. A phototransistor is a good candidate for a highly sensitive photodetector. In a metal oxide semiconductor field effect transistor (MOSFET), photo-generated carriers are accumulated underneath the gate region and modulate the majority current. This device is called a photo-MOSFET and it is widely used for optically isolated relays and image sensors. Compound semiconductor materials are essential if we are to extend the spectral range and sensitivity of photodetectors by flexibly designing the bandgap profile and achieving high carrier mobility. It is reported that high electron mobility transistors (HEMTs) have a responsivity of about 3 kA=W as a photodetecto
Contribution of the nucleon-hyperon reaction channels to K production in proton-nucleus collisions
The cross sections for producing K mesons in nucleon-hyperon elementary
processes are estimated assuming one-pion exchange and using the experimentally
known pion-hyperon cross sections. The results are implemented in a transport
model which is applied to calculation of proton-nucleus collisions. In
significant difference to earlier estimates for heavy-ion collisions the
inclusion of the nucleon-hyperon cross section roughly doubles the K
production in near-threshold proton-nucleus collisions
Cross-Field Plasma Acceleration and Potential Formation Induced by Electromagnetic Waves in a Relativistic Magnetized Plasma
Abstract It has been proved theoretically that particle acceleration along and across a magnetic field and electric field across a magnetic field can be induced by nonlinear Landau damping of almost perpendicularly propagating electrostatic waves in a relativistic magnetized plasma
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