Responsivity

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

Perovskite/Black Phosphorus/MoS2 Photogate Reversed Photodiodes with Ultrahigh Light On/Off Ratio and Fast Response

Abstract: As compared with epitaxial semiconductor devices, two-dimensional (2D) heterostructures offer alternative facile platforms for many optoelectronic devices. Among them, photovoltaic based photodetectors can give fast response, while the photogate devices can lead to high responsivity. Here, we report a 2D photogate photodiode, which combines the benefits of 2D black phosphorus/MoS2 photodiodes with the emerging potential of perovskite, to achieve both fast response and high responsivity. This device architecture is constructed based on the fast photovoltaic operation together with the high-gain photogating effect. Under reverse bias condition, the device exhibits high responsivity (11 A/W), impressive detectivity (1.3 × 1012 Jones), fast response (150/240 μs), and low dark current (3 × 10-11 A). All these results are already much better in nearly all aspects of performance than the previously reported 2D photodiodes operating in reverse bias, achieving the optimal balance between all figure-of-merits. Importantly, with a zero bias, the device can also yield high detectivity (3 × 1011 Jones), ultrahigh light on/off ratio (3 × 107), and extremely high external quantum efficiency (80%). This device architecture thus has a promise for high-efficiency photodetection and photovoltaic energy conversion.

High‐performance InGaAs photodetectors on Si and GaAs substrates

Abstract: In this work, we demonstrate record low dark current operation of InGaAs (1.55 μm) p‐i‐n photodetectors on both silicon and gallium arsenide substrates using a wafer bonding technique. The photodetectors were made by first bonding the p‐i‐n epitaxial layers to the Si and GaAs substrate followed by chemical removal of the host (InP) substrate from the p‐i‐n structure. The photodetector was then fabricated atop the newly exposed p‐i‐n epilayers. Dark currents of as low as 57 pA on a GaAs substrate and 0.29 nA on a Si substrate were measured under 5 V reverse bias. The responsivity at 1.55 μm wavelength was measured to be 1 A/W, corresponding to an external quantum efficiency of 80%. The series resistance measured across the bonded interface gave 17 Ω on GaAs and 350 Ω on Si, respectively.

Photojunction Field-Effect Transistor Based on a Colloidal Quantum Dot Absorber Channel Layer

Abstract: The performance of photodetectors is judged via high responsivity, fast speed of response, and low background current. Many previously reported photodetectors based on size-tuned colloidal quantum dots (CQDs) have relied either on photodiodes, which, since they are primary photocarrier devices, lack gain; or photoconductors, which provide gain but at the expense of slow response (due to delayed charge carrier escape from sensitizing centers) and an inherent dark current vs responsivity trade-off. Here we report a photojunction field-effect transistor (photoJFET), which provides gain while breaking prior photoconductors’ response/speed/dark current trade-off. This is achieved by ensuring that, in the dark, the channel is fully depleted due to a rectifying junction between a deep-work-function transparent conductive top contact (MoO3) and a moderately n-type CQD film (iodine treated PbS CQDs). We characterize the rectifying behavior of the junction and the linearity of the channel characteristics under illu...

Zero-biased near-ultraviolet and visible photodetector based on ZnO nanorods/n-Si heterojunction

Abstract: N-ZnO nanorods/n-silicon heterojunction was fabricated by growth of ZnO nanorods on a n-type silicon (111) wafer with a low-temperature aqueous solution method. Capacitance-voltage measurements revealed that after annealing at 900 °C in O2 ambient for 1 h, the heterojunction changed from abrupt N-ZnO nanorods/n-silicon to graded P-ZnO/n-silicon junction. The annealed diode showed good photoresponse in both the ultraviolet and visible regions with responsivity around 0.3 and 0.5 A/W without bias. The photoresponses toward ultraviolet and visible light were enhanced when the diode was under reverse and forward bias, respectively. The results were discussed in terms of phosphorus diffusion process and the band diagrams of the heterojunctions in this work.