Responsivity

About: Responsivity is a research topic. Over the lifetime, 9918 publications have been published within this topic receiving 186118 citations.

High sensitivity and fast response self-powered solar-blind ultraviolet photodetector with a β-Ga2O3/spiro-MeOTAD p–n heterojunction

Abstract: Solar-blind ultraviolet (UV) photodetectors are greatly desired in a number of areas in terms of military and civilian purposes, especially self-powered devices driven by the photovoltaic effect. Herein, a solar blind photodetector has been successfully achieved on a spiro-MeOTAD/β-Ga2O3 organic–inorganic hybrid construction. The fabricated photodetector can operate with a self-powered mode and shows an obvious photodetection with a narrow spectrum region, exhibiting a high responsivity (65 mA W−1) and a large external quantum efficiency (32%) under low power intensity (∼1 μW cm−2) UV illumination, at zero bias. Fortunately, the device shows a fast temporal pulse response (τrise ∼ 2.98 μs and τdecay ∼ 28.49 μs), which is superior to the previously reported Ga2O3 based self-powered photodetectors. More importantly, the photodetector can operate stably and shows good repeatability. These excellent performances of the device could be attributed to the pre-existing band alignment of the Ga2O3 and spiro-MeOTAD, and are comparable to and/or even higher than those of other self-powered solar-blind UV photodetectors, which indicates that a device configuration based on a Ga2O3/spiro-MeOTAD heterojunction is certified as an excellent candidate for a high sensitivity, ultrafast response and self-powered photo-detecting device for solar-blind UV signals.

Bias effects in high performance GaAs homojunction far-infrared detectors

Abstract: A high performance, bias tunable, p-GaAs homojunction interfacial workfunction internal photoemission far-infrared detector is demonstrated. A responsivity of 3.10±0.05 A/W, a quantum efficiency of 12.5%, and a detectivity D* of 5.9×1010 cmHz/W were obtained at 4.2 K for cutoff wavelengths from 80 to 100 μm. The bias dependences of the quantum efficiency, detectivity, and cutoff wavelength were measured and are well explained by the theoretical model. The effect of the layer number on detector performance and the uniformity of the detectors are discussed. A comparison with Ge:Ga photoconductive detectors suggests that similar or even better performance may be obtainable with a far-infrared detector.

Micromachined antenna-coupled uncooled microbolometers for terahertz imaging arrays

Abstract: In recent years our group has made significant progress toward the goal of a scalable, inexpensive terahertz imaging system for the detection of weapons concealed under clothing. By actively illuminating the subject under examination with only moderate source power (few milliwatts) the sensitivity constraints on the detector technology are significantly lessened compared to purely passive millimeter-wave detection. Last year, we demonstrated a fully planar, optically lithographed, uncooled terahertz imaging array with 120 pixels on a silicon substrate 75 mm in diameter. In this paper we present the recent progress on improving the responsivity of the individual microbolometers by a simple technique of surface micromachining to reduce the substrate thermal conduction. We describe the microbolometer array fabrication and present results on devices with a measured electrical responsivity of over 85 V/W (electrical NEP ~25 pW/rtHz), an improvement by a factor of two over current substrate-supported bolometers.

Improving CMOS-compatible Germanium photodetectors.

Abstract: We report design improvements for evanescently coupled Germanium photodetectors grown at low temperature. The resulting photodetectors with 10 μm Ge length manufactured in a commercial CMOS process achieve >0.8 A/W responsivity over the entire C-band, with a device capacitance of <7 fF based on measured data.