Responsivity

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

High-responsivity, normal-incidence long-wave infrared (λ∼7.2 μm) InAs/In0.15Ga0.85As dots-in-a-well detector

Abstract: Normal incidence InAs/In0.15Ga0.85As dots-in-a-well detectors operating at T=78 K with λp∼7.2 μm and a spectral width (Δλ/λ) of 35% are reported. The peak at 7.2 μm is attributed to the bound-to-bound transitions between the ground state of the dot and the states within the InGaAs well. A broad shoulder around 5 μm, which is attributed to the bound-to-continuum transition, is also observed. Calibrated blackbody measurements at a device temperature of 78 K yield a peak responsivity of 3.58 A/W (Vb=−1 V), peak detectivity=2.7×109 cm Hz1/2/W (Vb=−0.3 V), conversion efficiency of 57% and a gain ∼25.

Strain-engineered high-responsivity MoTe2 photodetector for silicon photonic integrated circuits

Abstract: In integrated photonics, specific wavelengths such as 1,550 nm are preferred due to low-loss transmission and the availability of optical gain in this spectral region. For chip-based photodetectors, two-dimensional materials bear scientifically and technologically relevant properties such as electrostatic tunability and strong light–matter interactions. However, no efficient photodetector in the telecommunication C-band has been realized with two-dimensional transition metal dichalcogenide materials due to their large optical bandgaps. Here we demonstrate a MoTe2-based photodetector featuring a strong photoresponse (responsivity 0.5 A W–1) operating at 1,550 nm in silicon photonics enabled by strain engineering the two-dimensional material. Non-planarized waveguide structures show a bandgap modulation of 0.2 eV, resulting in a large photoresponse in an otherwise photoinactive medium when unstrained. Unlike graphene-based photodetectors that rely on a gapless band structure, this photodetector shows an approximately 100-fold reduction in dark current, enabling an efficient noise-equivalent power of 90 pW Hz–0.5. Such a strain-engineered integrated photodetector provides new opportunities for integrated optoelectronic systems. A strain-induced absorption-enhanced MoTe2-based silicon photonic microring-integrated photodetector is demonstrated, featuring high responsivity of ~0.5 A W–1 at 1,550 nm, with a low noise-equivalent power of 90 pW Hz–0.5.

Selenium-Doped Black Phosphorus for High-Responsivity 2D Photodetectors

Abstract: Se-doped black phosphorus (BP) crystal, in centimeter scale, is synthesized by a scalable gas-phase growth method under mild conditions. The Se-doped BP exhibits high quality with excellent electrical properties. The Se dope induces over 20-fold enhancement of responsivity (R) for BP-based 2D photodetectors, resulting in a high R and external quantum efficiency of 15.33 A W-1 and 2993%, respectively.

Pulsed laser deposition of gallium oxide films for high performance solar-blind photodetectors

Abstract: Monoclinic gallium oxide thin films were grown on (0001) sapphire at various substrate temperatures ranging from 400 to 1000 °C by pulsed laser deposition using a KrF excimer laser. The structural, optical and compositional properties of the films were analyzed by using x-ray diffraction, transmission electron microscopy, optical transmittance, and Rutherford backscattering spectroscopy. As the substrate temperature was increased to 800 °C, the gallium oxide film possesses single crystalline phase with a preferred growth orientation of (−201) plane and higher crystal quality than those at the other temperatures. Optical transmittance measurements reveal the films grown at 600-1000 °C exhibit a clear absorption edge at the deep ultraviolet region around 250 nm wavelength. Based on the results of Rutherford backscattering spectroscopy, the O/Ga ratio of gallium oxide film increased gradually with increasing substrate temperature. When the substrate temperature was raised to 800-1000 °C, the film composition was close to the formation of Ga2O3, indicating the O vacancies and defects were reduced. Furthermore, the films grown at 600 and 800 °C were chosen to fabricate solar-blind metal-semiconductor-metal photodetectors. At an applied bias of 5 V, the photodetector prepared with 800 °C-grown film has a lower dark current of 1.2 × 10−11 A and a higher responsivity of 0.903 A/W (at a wavelength of 250 nm) than those with 600 °C-grown films. The better device performance is ascribed to the higher crystal quality and fewer O vacancies in the 800 °C-grown film. Moreover, the results indicate the gallium oxide films presented in this study have high potential for deep ultraviolet photodetector applications.