Responsivity

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

Visible-blind deep-ultraviolet Schottky photodetector with a photocurrent gain based on individual Zn2GeO4 nanowire

Abstract: We report on the visible-blind deep-ultraviolet (DUV) photodetectors with metal-semiconductor-metal (MSM) Schottky contacts based on individual Zn2GeO4 nanowire single-crystals. At an 8 V bias voltage, the device shows an extremely low dark current (<0.1 pA), a responsivity of 38.3 A/W (corresponding gain ∼200), a high DUV-to-visible discrimination ratio up to ∼104, and a relatively fast response time upon 245 nm DUV illumination. By analyzing the light-intensity-dependent photocurrent generation and carrier transport, the photogenerated holes trapped in Schottky barrier and shrinking of depletion region under DUV illumination at the metal/Zn2GeO4 interface are proposed for the carrier injection and the photocurrent gain.

A Switchable High-Sensitivity Photodetecting and Photovoltaic Device with Perovskite Absorber.

Abstract: Amplified photocurrent gain has been obtained by photodiodes of inorganic semiconductors such as GaAs and Si. The avalanche photodiode, developed for high-sensitivity photodetectors, requires an expensive vapor-phase epitaxy manufacture process and high driving voltage (50–150 V). Here, we show that a low-cost solution-processed device using a planar-structured ferroelectric organo-lead triiodide perovskite enables light detection in a large dynamic range of incident power (10–7–10–1 W cm–2) by switching with small voltage (−0.9 to +0.5 V). The device achieves significantly high external quantum conversion efficiency (EQE) up to 2.4 × 105% (gain value of 2400) under weak monochromatic light. On a single dual-functional device, incident small power (0.2–100 μW cm–2) and medium to large power (>0.1 mW cm–2) are captured by reverse bias and forward bias modes, respectively, with linear responsivity of current. For weak light detection, the device works with a high responsivity value up to 620 A W–1.

Solar blind photodetector based on epitaxial zinc doped Ga2O3 thin film

Abstract: We report on the fabrication and characterization of solar blind photodetectors (SBPs) based on undoped β-Ga2O3 and Zn doped (∼5 × 1020 cm−3) β-Ga2O3 (ZnGaO) epitaxial films with cutoff wavelength of ∼260 nm. The epilayers were grown on c-sapphire by the metal organic chemical vapor deposition technique and their structural, electrical and optical properties were characterized using various methods. As grown films have a large number of defects, resulting in detectors with enhanced internal gain, hence, high spectral responsivity >103 A/W. Post growth annealing in oxygen improved the quality of the epilayers, leading to detectors with reduced dark current (∼nA to ∼pA) and increased out of band rejection ratio. At 20 V bias, a ZnGaO detector showed a peak responsivity of 210 A/W (at 232 nm) and an out of band rejection ratio (i.e., R232 nm/R320 nm) of 5 × 104. Alternatively, for a β-Ga2O3 detector these parameters were found to be five times and three times lower, respectively, suggesting that ZnGaO detectors have superior performance characteristics. These results provide a roadmap toward achieving high responsivity SBPs based on epitaxial ZnGaO films, laying a solid foundation for future applications.

Multifunctional zinc oxide thin films for high-performance UV photodetectors and nitrogen dioxide gas sensors

Abstract: In order to find new approaches for sensor devices; ZnO based gas sensors and UV photodetectors with higher sensitivity and responsivity were fabricated. ZnO thin films were synthesized by using inexpensive successive ionic layers by an adsorption and reaction method (SILAR) on the amorphous glass substrate. The fabricated metal���semiconductor–metal (MSM) UV photoconductive detector shows excellent photoresponse with fast response and recovery times (18 s and 24 s) under UV illumination (wavelength −365 nm and power density −1.8 μW cm−2) at 5 V bias voltage. The detector shows an ohmic nature between metal semiconductor contacts with spectral responsivity 185 A W−1. Gas sensing performance for detecting NO2 gas was studied at a relatively low operating temperature of 175 °C and 20.52 response was observed for the optimized film for a 60 ppm gas concentration. The sensor has good repeatability along with a quick response time, whereas it has a relatively high recovery time. The sensor is highly selective towards NO2 gas as compared to other gases, and has a lower detection limit of 10 ppm at an operating temperature of 175 °C. The present study opens up possibilities for the extensive study of ZnO thin film based sensor devices using a simple chemical deposition method (SILAR).

Stable, Fast UV–Vis–NIR Photodetector with Excellent Responsivity, Detectivity, and Sensitivity Based on α-In2Te3 Films with a Direct Bandgap

Abstract: Photoelectric conversion is of great importance to extensive applications. However, thus far, photodetectors integrated with high responsivity, excellent detectivity, large phototo-dark current ratio, fast response speed, broad spectral range, and good stability are rarely achieved. Herein, we deposited large-scale and high-quality polycrystalline indium sesquitelluride (α-In2Te3) films via pulsed-laser deposition. Then, we demonstrated that the photodetectors made of the prepared α-In2Te3 films possess stable photoswitching behavior from 370 to 1064 nm and short response time better than ca. 15 ms. At a source-drain voltage of 5 V, the device achieves a high responsivity of 44 A/W, along with an outstanding detectivity of 6 × 10(12) cm H(1/2) W(-1) and an excellent sensitivity of 2.5 × 10(5) cm(2)/W. All of these figures-of-merit are the best among those of the reported α-In2Te3 photodetectors. In fact, they are comparable to the state-of-the-art commercial Si and Ge photodetectors. For the first time, we established the theoretical evidence that α-In2Te3 possesses a direct bandgap structure, which reasonably accounts for the superior photodetection performances above. Importantly, the device exhibits a good stability against the multiple photoswitching operation and ambient environment, along with no obvious voltage-scan hysteresis. These excellent figures-of-merit, together with the broad spectral range and good stability, underscore α-In2Te3 as a promising candidate material for next-generation photodetection.