Responsivity

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

Flexible and Self-Powered Photodetector Arrays Based on All-Inorganic CsPbBr3 Quantum Dots

Abstract: Flexible devices are garnering substantial interest owing to their potential for wearable and portable applications. Here, flexible and self-powered photodetector arrays based on all-inorganic perovskite quantum dots (QDs) are reported. CsBr/KBr-mediated CsPbBr3 QDs possess improved surface morphology and crystallinity with reduced defect densities, in comparison with the pristine ones. Systematic material characterizations reveal enhanced carrier transport, photoluminescence efficiency, and carrier lifetime of the CsBr/KBr-mediated CsPbBr3 QDs. Flexible photodetector arrays fabricated with an optimum CsBr/KBr treatment demonstrate a high open-circuit voltage of 1.3 V, responsivity of 10.1 A W-1 , specific detectivity of 9.35 × 1013 Jones, and on/off ratio up to ≈104 . Particularly, such performance is achieved under the self-powered operation mode. Furthermore, outstanding flexibility and electrical stability with negligible degradation after 1600 bending cycles (up to 60°) are demonstrated. More importantly, the flexible detector arrays exhibit uniform photoresponse distribution, which is of much significance for practical imaging systems, and thus promotes the practical deployment of perovskite products.

Integration of perovskite and polymer photoactive layers to produce ultrafast response, ultraviolet-to-near-infrared, sensitive photodetectors

Abstract: Low-cost organic photodetectors have shown sensitivity levels comparable to those of inorganic photodetectors, but with response speeds generally limited to the megahertz range due to the low mobility of organic semiconductors. Here, we integrated organic–inorganic hybrid perovskite (OIHP) photoactive layers with low-bandgap organic bulk-heterojunction (BHJ) layers to produce a device that combined the advantages of the two types of photodetectors. Integrating methylammonium lead triiodide (CH3NH3PbI3) with a low-bandgap BHJ layer extended the response of perovskite photodetectors to a wavelength of 1000 nanometers without deteriorating the responsivity and specific detectivity of either type of photodetector. The high mobility of charge carriers in CH3NH3PbI3 allowed the constraints of the resistance–capacitance constant to be relieved so that the device response speed could be increased dramatically. A response time of five nanoseconds was measured for incident infrared light from the device with an active area of 0.1 square millimeters, which represents the state-of-the-art performance for organic-based photodetectors.

Optic sensors of high refractive-index responsivity and low thermal cross sensitivity that use fiber Bragg gratings of >80° tilted structures

Abstract: For the first time to the authors' knowledge, fiber Bragg gratings (FBGs) with >80° tilted structures nave been fabricated and characterized. Their performance in sensing temperature, strain, and the surrounding medium's refractive index was investigated. In comparison with normal FBGs and long-period gratings (LPGs), >80° tilted FBGs exhibit significantly higher refractive-index responsivity and lower thermal cross sensitivity. When the grating sensor was used to detect changes in refractive index, a responsivity as high as 340 nm/refractive-index unit near an index of 1.33 was demonstrated, which is three times higher than that of conventional LPGs. © 2006 Optical Society of America.

High-performance solar-blind ultraviolet photodetector based on mixed-phase ZnMgO thin film

Abstract: High Mg content mixed-phase Zn0.38Mg0.62O was deposited on a-face sapphire by plasma-assisted molecular beam epitaxy, based on which a metal-semiconductor-metal solar-blind ultraviolet (UV) photodetector was fabricated. The dark current is only 0.25 pA at 5 V, which is much lower than that of the reported mixed-phase ZnMgO photodetectors. More interestingly, different from the other mixed-phase ZnMgO photodetectors containing two photoresponse bands, this device shows only one response peak and its −3 dB cut-off wavelength is around 275 nm. At 10 V, the peak responsivity is as high as 1.664 A/W at 260 nm, corresponding to an internal gain of ∼8. The internal gain is mainly ascribed to the interface states at the grain boundaries acting as trapping centers of photogenerated holes. In view of the advantages of mixed-phase ZnMgO photodetectors over single-phase ZnMgO photodetectors, including easy fabrication, high responsivity, and low dark current, our findings are anticipated to pave a new way for the dev...

Terahertz detection by high-electron-mobility transistor: Enhancement by drain bias

Abstract: We report on a regime of operation of high-electron-mobility-transistor (HEMT) terahertz detectors, in which we apply a constant drain bias. The drain bias dependence of the gate-to-source and gate-to-drain capacitances results in a much greater asymmetry in the boundary conditions for plasma waves and greatly enhances the HEMT detector responsivity. The measured responsivity increases with the drain current by more than an order of magnitude and saturates at a saturation drain current for a given gate bias. These results confirm our model linking the responsivity increase to the drain bias dependence of the HEMT capacitances.