Responsivity

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

PtTe2‐Based Type‐II Dirac Semimetal and Its van der Waals Heterostructure for Sensitive Room Temperature Terahertz Photodetection

Abstract: Recent years have witnessed rapid progresses made in the photoelectric performance of two-dimensional materials represented by graphene, black phosphorus, and transition metal dichalcogenides. Despite significant efforts, a photodetection technique capable for longer wavelength, higher working temperature as well as fast responsivity, is still facing huge challenges due to a lack of best among bandgap, dark current, and absorption ability. Exploring topological materials with nontrivial band transport leads to peculiar properties of quantized phenomena such as chiral anomaly, and magnetic-optical effect, which enables a novel feasibility for an advanced optoelectronic device working at longer wavelength. In this work, the direct generation of photocurrent at low energy terahertz (THz) band at room temperature is implemented in a planar metal-PtTe2 -metal structure. The results show that the THz photodetector based on PtTe2 with bow-tie-type planar contacts possesses a high photoresponsivity (1.6 A W-1 without bias voltage) with a response time less than 20 µs, while the PtTe2 -graphene heterostructure-based detector can reach responsivity above 1.4 kV W-1 and a response time shorter than 9 µs. Remarkably, it is already exploitable for large area imaging applications. These results suggest that topological semimetals such as PtTe2 can be ideal materials for implementation in a high-performing photodetection system at THz band.

Tellurene Photodetector with High Gain and Wide Bandwidth.

Abstract: Two-dimensional (2D) semiconductors have been extensively explored as a new class of materials with great potential. In particular, black phosphorus (BP) has been considered to be a strong candidate for applications such as high-performance infrared photodetectors. However, the scalability of BP thin film is still a challenge, and its poor stability in the air has hampered the progress of the commercialization of BP devices. Herein, we report the use of hydrothermal-synthesized and air-stable 2D tellurene nanoflakes for broadband and ultrasensitive photodetection. The tellurene nanoflakes show high hole mobilities up to 458 cm2/V·s at ambient conditions, and the tellurene photodetector presents peak extrinsic responsivity of 383 A/W, 19.2 mA/W, and 18.9 mA/W at 520 nm, 1.55 μm, and 3.39 μm light wavelength, respectively. Because of the photogating effect, high gains up to 1.9 × 103 and 3.15 × 104 are obtained at 520 nm and 3.39 μm wavelength, respectively. At the communication wavelength of 1.55 μm, the tellurene photodetector exhibits an exceptionally high anisotropic behavior, and a large bandwidth of 37 MHz is obtained. The photodetection performance at different wavelength is further supported by the corresponding quantum molecular dynamics (QMD) simulations. Our approach has demonstrated the air-stable tellurene photodetectors that fully cover the short-wave infrared band with ultrafast photoresponse.

MoTe2 p-n Homojunctions Defined by Ferroelectric Polarization.

Abstract: Doped p-n junctions are fundamental electrical components in modern electronics and optoelectronics. Due to the development of device miniaturization, the emergence of two-dimensional (2D) materials may initiate the next technological leap toward the post-Moore era owing to their unique structures and physical properties. The purpose of fabricating 2D p-n junctions has fueled many carrier-type modulation methods, such as electrostatic doping, surface modification, and element intercalation. Here, by using the nonvolatile ferroelectric field polarized in the opposite direction, efficient carrier modulation in ambipolar molybdenum telluride (MoTe2 ) to form a p-n homojunction at the domain wall is demonstrated. The nonvolatile MoTe2 p-n junction can be converted to n-p, n-n, and p-p configurations by external gate voltage pulses. Both rectifier diodes exhibited excellent rectifying characteristics with a current on/off ratio of 5 × 105 . As a photodetector/photovoltaic, the device presents responsivity of 5 A W-1 , external quantum efficiency of 40%, specific detectivity of 3 × 1012 Jones, fast response time of 30 µs, and power conversion efficiency of 2.5% without any bias or gate voltages. The MoTe2 p-n junction presents an obvious short-wavelength infrared photoresponse at room temperature, complementing the current infrared photodetectors with the inadequacies of complementary metal-oxide-semiconductor incompatibility and cryogenic operation temperature.

Back-illuminated GaN/AlGaN heterojunction photodiodes with high quantum efficiency and low noise

Abstract: Back-illuminated GaN/AlGaN ultraviolet (UV) heterojunction photodiodes with high quantum efficiencies are demonstrated. Photovoltaic (zero bias) responsivity of 0.2 A/W at 355 nm was achieved. The improved efficiencies primarily arise from the use of AlGaN/GaN heterojunction in which photons are absorbed within the p-n junction thus eliminates carrier losses due to surface recombination and diffusion processes in previously reported homojunction devices. Very high dark impedance and large visible rejection ratio were obtained. These results indicate high quality GaN/AlGaN interface and efficient photocarrier collection in the photodiode.

InP-based waveguide-integrated photodetector with 100-GHz bandwidth

Abstract: A waveguide-integrated photodetector is presented, exhibiting a bandwidth of 100 GHz The responsivity amounts to 066 A/W and the PDL is below 09 dB The detector chip is designed to obtain a Bessel filter-shaped transfer characteristic when packaged in a module comprising a 1-mm connector