Responsivity

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

Design and performance of blocked-impurity-band detector focal plane arrays

Abstract: Blocked-Impurity-Band (BIB) extrinsic silicon (Si:As) detectors have demonstrated high sensitivity and quantum efficiency in the long wavelength infrared (LWIR) spectral region (to 28 microns) as well as wide frequency response, low optical crosstalk, nuclear radiation hardness, and stable, predictable performance. Furthermore, it has been demonstrated that SWItched mosFET (SWIFET) multiplexers provide a low noise readout approach for use with BIB detectors. This paper describes the state-of-the-art of multiplexed BIB detector hybrid focal plane arrays (HFPAs). The principle of operation and performance of optimized BIB and Back Illuminated BIB (BIBIB) detectors are presented. The SWIFET multiplexer, including necessary circuitry for BIBIB detector readout, has been designed and fabricated using a newly developed process for cryogenic (<20K) MOS electronics which avoids anomalies (lack of device isolation, excess noise, and long time constants) associated with conventional silicon processes. A description of the design and operation of this multiplexer is given. A number of uniform, highly responsive, 500 element HFPAs have been fabricated and their performance evaluated. The characterization measurements, to be described in the paper, include evaluation of detector dark current, responsivity, noise for various operating conditions, and uniformity of array characteristics. The results obtained and presented demonstrate that focal plane arrays with excellent, unprecedented, LWIR performance have been realized with Blocked-Impurity-Band detector technology.

Sb2S3/Spiro-OMeTAD Inorganic–Organic Hybrid p–n Junction Diode for High Performance Self-Powered Photodetector

Abstract: Organic–inorganic hybrid diodes are very promising for solution processing, low cost, high performance optoelectronic devices. Here, we report a high quality p–n heterojunction diode composed of n-type inorganic Sb2S3 and p-type organic 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD) with a rectification ratio of ∼102 at an applied bias of 1 V. On illumination with visible light (470 nm, 1.82 mW/cm2), the current value in our device becomes 8 × 102 times that of its dark value even at a zero bias condition. The estimated responsivity value at zero bias is 0.087 A/W which is so far the highest reported for any organic–inorganic hybrid photodiode, to the best of our knowledge. It also exhibits a fast photoresponse time of <25 ms (instrumental limit). More importantly, our device can also detect visible light with power density as low as 8 μW/cm2 with a photocurrent density of 1.2 μA/cm2 and a photocurrent to dark current ratio of more than 8. We also demonstrate that the...

Photoconductive gain in solar-blind ultraviolet photodetector based on Mg0.52Zn0.48O thin film

Abstract: An ultraviolet photodetector was fabricated on MgZnO thin film grown by metal-organic chemical vapor deposition. The peak response of the device centers at 238 nm and cutoff wavelength is 253 nm. The peak responsivity is 129 mA/W at 15 V bias, and the UV/visible reject ratio is 4 orders of magnitude. Internal gain is due to the hole trapping at interface that brings low response speed. Native defects at the Au/MgZnO interface degrade the barrier effect, which caused large dark current and high visible response.

High-sensitivity β-Ga_2O_3 solar-blind photodetector on high-temperature pretreated c-plane sapphire substrate

Abstract: Recently, monoclinic Ga2O3 (β-Ga2O3) photodetectors (PDs) have been extensively studied for various commercial and military applications due to the merits of intrinsic solar rejection, high gain, and great compactness. In this work, c-plane sapphire substrates were annealed under different temperatures in a vacuum furnace prior to the molecular beam epitaxy (MBE) of β-Ga2O3 thin film, which yielded a smoother surface and even a terrace-and-step-like morphology on the substrate, resulting in improved crystallinity of the epitaxial film. Accordingly, both the dark and photo currents of β-Ga2O3 metal-semiconductor-metal (MSM) PDs were increased by the enhanced carrier mobility (μ) of the more crystalline film. However, the substrate-annealing temperature must be sufficiently high to offset the rise of the dark current and thus achieve a remarkable improvement in the photodetection properties. As a result, the PD fabricated on the 1050 °C-annealed substrate exhibited extremely high sensitivity, for example, high responsivity (R) of 54.9 A/W and large specific detectivity (D*) of 3.71 × 1014 Jones. Both parameters were increased by one order of magnitude because of the combined effects of the dramatic increase in μ and the effective reduction in defect-related recombination centers. Nevertheless, the latter also prolonged the recovery time of the PD. These findings suggest another way to develop β-Ga2O3 PD with extremely high sensitivity.

Characterization of uncooled bolometer with vanadium tungsten oxide infrared active layer

Abstract: A surface micromachining uncooled infrared detector with an optimized vanadium alloy oxide layer is fabricated, based on low temperature annealing of V–W alloy oxide layer. Vanadium oxide is a promising material for an uncooled bolometer, due to its high temperature coefficient of resistance at room temperature. An infrared active layer is needed to be with the reflective layer to enhance its IR absorption. Test bolometers are successfully fabricated and then are radiated by an IR laser source at various power levels with a chopper in a frequency range of 1–500 Hz. The responsivity and the noise of the test bolometer are measured and the detectivity is calculated. From the results, the calculated detectivity is 1.1 × 107 cm Hz1/2 W−1. Bolometer detectivity can be increased further if the noise in the device is reduced.