TL;DR: The tailored selection of absorption onset energy through the quantum size effect, combined with deliberate engineering of the sequence of nanoparticle fusing and surface trap functionalization, underlie the superior performance achieved in this readily fabricated family of devices.
Abstract: Solution-processed electronic and optoelectronic devices offer low cost, large device area, physical flexibility and convenient materials integration compared to conventional epitaxially grown, lattice-matched, crystalline semiconductor devices. Although the electronic or optoelectronic performance of these solution-processed devices is typically inferior to that of those fabricated by conventional routes, this can be tolerated for some applications in view of the other benefits. Here we report the fabrication of solution-processed infrared photodetectors that are superior in their normalized detectivity (D*, the figure of merit for detector sensitivity) to the best epitaxially grown devices operating at room temperature. We produced the devices in a single solution-processing step, overcoating a prefabricated planar electrode array with an unpatterned layer of PbS colloidal quantum dot nanocrystals. The devices showed large photoconductive gains with responsivities greater than 10(3) A W(-1). The best devices exhibited a normalized detectivity D* of 1.8 x 10(13) jones (1 jones = 1 cm Hz(1/2) W(-1)) at 1.3 microm at room temperature: today's highest performance infrared photodetectors are photovoltaic devices made from epitaxially grown InGaAs that exhibit peak D* in the 10(12) jones range at room temperature, whereas the previous record for D* from a photoconductive detector lies at 10(11) jones. The tailored selection of absorption onset energy through the quantum size effect, combined with deliberate engineering of the sequence of nanoparticle fusing and surface trap functionalization, underlie the superior performance achieved in this readily fabricated family of devices.
TL;DR: This work demonstrates polymer photodetectors with broad spectral response fabricated by using a small-band-gap semiconducting polymer blended with a fullerene derivative that can exceed the response of an inorganic semiconductor detector at liquid helium temperature.
Abstract: Sensing from the ultraviolet-visible to the infrared is critical for a variety of industrial and scientific applications. Today, gallium nitride-, silicon-, and indium gallium arsenide--based detectors are used for different sub-bands within the ultraviolet to near-infrared wavelength range. We demonstrate polymer photodetectors with broad spectral response (300 to 1450 nanometers) fabricated by using a small-band-gap semiconducting polymer blended with a fullerene derivative. Operating at room temperature, the polymer photodetectors exhibit detectivities greater than 10(12) cm Hz(1/2)/W and a linear dynamic range over 100 decibels. The self-assembled nanomorphology and device architecture result in high photodetectivity over this wide spectral range and reduce the dark current (and noise) to values well below dark currents obtained in narrow-band photodetectors made with inorganic semiconductors.
TL;DR: In this article, the performance of infrared thermal detectors as compared to photon detectors is investigated and an overview of focal plane array architecture is given with emphasis on monolithic and hybrid structures.
TL;DR: A review of the history, the present status and possible future developments of HgCdTe ternary alloy for infrared (IR) detector applications is presented in this article.
Abstract: This article reviews the history, the present status and possible future developments of HgCdTe ternary alloy for infrared (IR) detector applications. HgCdTe IR detectors have been intensively developed since the first synthesis of this material in 1958. This article summarizes the fundamental properties of this versatile narrow gap semiconductor, and relates the material properties to its successful applications as an IR photoconductive and photovoltaic detector material. An emphasis is put on key developments in the crystal growth and their influence on device evolution. Competitive technologies to HgCdTe ternary alloy are also presented. Recent advances of backside illuminated HgCdTe heterojunction photodiodes have enabled a third generation of multispectral instruments for remote sensing applications and have led to the practicality of multiband IR focal plane array technology. Finally, evaluation of HgCdTe for room temperature long wavelength IR applications is presented. (Some figures in this article are in colour only in the electronic version)
TL;DR: The nBn detector as discussed by the authors eliminates the Shockley-Read-Hall generation currents and reduces the amount of dark current and noise in the detector, which enables it to operate at background-limited infrared photodetection conditions at significantly higher temperatures than conventional midwave infrared detectors.
Abstract: This letter presents a type of infrared detector named the nBn detector. The nBn design essentially eliminates Shockley-Read-Hall generation currents. The result is greatly reduced dark current and noise, compared to other midwave infrared detectors, such as p-n photodiodes. This enables the nBn to operate at background-limited infrared photodetection conditions at significantly higher temperatures than conventional midwave infrared detectors and have greater detectivity near room temperature. The nBn is demonstrated in InAs and InAsSb materials, exhibiting cutoff wavelengths of 3.4 and 4.2μm, respectively.