نتایج جستجو برای: detectivity
تعداد نتایج: 428 فیلتر نتایج به سال:
2014 Up-conversion by APTE effect (Addition de Photons par Transferts d’Energie) in (Yb3+, Er3+) doped vitroceramics is used for the summation of 1.5 03BCm photons (signal) with 0.96 03BCm (pump). We discuss the different transfers schemes giving respectively the useful signal the losses and the noises in order to obtain a high detectivity IRQC (Infra Red Quantum Counter). Optimizing the vitroc...
We report an individually addressable Ti∕GaAs metal-semiconductor hybrid optical nanosensor with positive photoresistance and a sensitivity that increases as the device dimensions shrink. The underlying physics relates to the crossover from ballistic to diffusive transport of the photoinduced carriers and the geometric enhancement of the effect associated with a Schottky-barrier-coupled paralle...
We propose mid/far-infrared photodetectors based on coherent sum-frequency generation in a near-resonant cascade of interband and intersubband transitions in high optical nonlinearity asymmetric quantum well structures. Such structures can yield high detectivity and responsivity in the bandwidth of the order of 30% of a central frequency in the mid-infrared range. Resonant up-conversion detecto...
We report on effective sulfur-based passivation treatments of type-II InAs/GaSb strained layer superlattice detectors (100% cut-off wavelength is 9.8 lm at 77 K). The electrical behavior of detectors passivated by electrochemical sulfur deposition (ECP) and thioacetamide (TAM) was evaluated for devices of various sizes. ECP passivated detectors with a perimeter-to-area ratio of 1600 cm 1 exhibi...
A diagonal optically active transition in a quantum cascade detector is introduced as optimization parameter to obtain quality factor matching between a photodetector and a cavity. A more diagonal transition yields both higher extraction efficiency and lower noise, while the reduction of the absorption strength is compensated by the resonant cavity. The theoretical limits of such a scheme are o...
A dual-band superlattice quantum dot infrared photodetector, providing bias-selectability of the response peaks, is demonstrated. The active region consists of two quantum dot superlattices separated by a graded barrier, enabling photocurrent generation only in one superlattice for a given bias polarity. Two response bands, one consisting of three peaks at 2.9, 3.2, and 4.9 m and the other cons...
Several designs for Fresnel zone plate lenses (FZPLs) to be used in conjunction with antenna-coupled infrared detectors have been fabricated and tested. The designs comprise square and circular FZPLs with different numbers of Fresnel zones working in transmissive or reflective modes designed to focus infrared energy on a square-spiral antenna connected to a microbolometer. A 163x maximum increa...
The performance of organic photodetectors is steadily improving, and the specific detectivity, as a key figure merit, has reached values 1012–1013 Jones, i.e., comparable to that silicon diodes but still considerably lower than intrinsic limit. As with other semiconductor devices, electrical state-of-the art photodiodes (OPDs) presently determined high degree by presence chemical impurities or ...
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