Responsivity

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

High responsivity of amorphous indium gallium zinc oxide phototransistor with Ta2O5 gate dielectric

Abstract: This study investigates the electrical performance of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) with a Ta2O5 gate dielectric under monochromatic illumination. The relationship between the phototransistor performance and oxygen partial pressure is determined. The oxygen content of the a-IGZO channel significantly affects the electrical and optical characteristics of a-IGZO TFTs. At applied gate biases of 0, 0, and 0.25 V, oxygen partial pressures of 0%, 0.1%, and 0.2% yielded measured device responsivities of 0.23, 0.44, and 4.75 A/W, respectively. Oxygen content can be used to control the mobility of TFTs, which can amplify photocurrent and enhance the responsivity of a-IGZO TFTs with a Ta2O5 gate dielectric.

Increasing Efficiency, Speed, and Responsivity of Vanadium Dioxide Based Photothermally Driven Actuators Using Single-Wall Carbon Nanotube Thin-Films

Abstract: Vanadium dioxide (VO2)-based actuators have demonstrated great performance in terms of strain energy density, speed, reversible actuation, programming capabilities, and large deflection. The relative low phase transition temperature of VO2 (∼68 °C) gives this technology an additional advantage over typical thermal actuators in terms of power consumption. However, this advantage can be further improved if light absorption is enhanced. Here we report a VO2-based actuator technology that incorporates single-wall carbon nanotubes (SWNTs) as an effective light absorber to reduce the amount of photothermal energy required for actuation. It is demonstrated that the chemistry involved in the process of integrating the SWNT film with the VO2-based actuators does not alter the quality of the VO2 film, and that the addition of such film enhances the actuator performance in terms of speed and responsivity. More importantly, the results show that the combination of VO2 and SWNT thin films is an effective approach to i...

Using Bulk Heterojunctions and Selective Electron Trapping to Enhance the Responsivity of Perovskite–Graphene Photodetectors

Abstract: Graphene field effect transistor sensitized by a layer of semiconductor (sensitizer/GFET) is a device structure that is investigated extensively for ultrasensitive photodetection. Among others, organometallic perovskite semiconductor sensitizer has the advantages of long carrier lifetime and solution processable. A further step to improve the responsivity is to design a structure that can promote electron–hole separation and selective carrier trapping in the sensitizer. Here, the use of a hybrid perovskite–organic bulk heterojunction (BHJ) as the light sensitizer to achieve this goal is demonstrated. Our spectroscopy and device measurements show that the CH3NH3PbI3–PCBM BHJ/GFET device has improved charge separation yield and carrier lifetime as compared to a reference device with a CH3NH3PbI3 sensitizer only. The key to these enhancement is the presence of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), which acts as charge separation and electron trapping sites, resulting in a 30-fold increase in the photoresponsivity. This work shows that the use of a small amount of electron or hole acceptors in the sensitizer layer can be an effective strategy for improving and tuning the photoresponsivity of sensitizer/GFET photodetectors.

WSe2 Photovoltaic Device Based on Intramolecular p-n Junction.

Abstract: High quality p-n junctions based on 2D layered materials (2DLMs) are urgent to exploit, because of their unique properties such as flexibility, high absorption, and high tunability which may be utilized in next-generation photovoltaic devices. Based on transfer technology, large amounts of vertical heterojunctions based on 2DLMs are investigated. However, the complicated fabrication process and the inevitable defects at the interfaces greatly limit their application prospects. Here, an in-plane intramolecular WSe2 p-n junction is realized, in which the n-type region and p-type region are chemically doped by polyethyleneimine and electrically doped by the back-gate, respectively. An ideal factor of 1.66 is achieved, proving the high quality of the p-n junction realized by this method. As a photovoltaic detector, the device possesses a responsivity of 80 mA W-1 (≈20% external quantum efficiency), a specific detectivity of over 1011 Jones and fast response features (200 µs rising time and 16 µs falling time) at zero bias, simultaneously. Moreover, a large open-circuit voltage of 0.38 V and an external power conversion efficiency of ≈1.4% realized by the device also promises its potential in microcell applications.

Flexible Photodiodes Based on Nitride Core/Shell p-n Junction Nanowires

Abstract: A flexible nitride p-n photodiode is demonstrated. The device consists of a composite nanowire/polymer membrane transferred onto a flexible substrate. The active element for light sensing is a vertical array of core/shell p–n junction nanowires containing InGaN/GaN quantum wells grown by MOVPE. Electron/hole generation and transport in core/shell nanowires are modeled within nonequilibrium Green function formalism showing a good agreement with experimental results. Fully flexible transparent contacts based on a silver nanowire network are used for device fabrication, which allows bending the detector to a few millimeter curvature radius without damage. The detector shows a photoresponse at wavelengths shorter than 430 nm with a peak responsivity of 0.096 A/W at 370 nm under zero bias. The operation speed for a 0.3 × 0.3 cm2 detector patch was tested between 4 Hz and 2 kHz. The −3 dB cutoff was found to be ∼35 Hz, which is faster than the operation speed for typical photoconductive detectors and which is c...