Group I−III−VI 2 semiconductors are promising for the fabrication of electronic and photoelectronic devices because of their tunable band gaps and intensive absorption in visible and near-infrared regions. Here, ternary AgInTe 2 nanostructures have been synthesized via a facilely designed solution-phase procedure at 240−280 °C from AgNO 3 and In(acac) 3 in oleylamine reacted with TeO 2 dissolved in 1-dodecanethiol. They illustrate truncated quasitetrahedrally geometrical shapes from the phosphine-free solution synthetic route and could be spin-coated on silicon wafer to set up a vertical AgInTe 2 /Si heterojunction-based photodetector. The device is highly sensitive to visible and near-infrared illuminance and has remarkable photoresponsive properties with an on/off switch ratio of 780 at a reverse bias of −5 V, a high responsivity (2.82 A W −1 ), specific detectivity (8.12 × 10 11 Jones), and a low noise equivalent power (2.46 × 10 −13 W Hz −1/2 ) at a bias of −2 V. Especially, the device exhibits fast response speeds (τ rise = 5.2 μs, τ fall = 18.4 μs), which would be a vital figure of merit for its technical application. The present work offers an available strategy for the tunable synthesis of ternary and even multiple-component tellurides beyond the demonstrated high-quality AgInTe 2 nanostructures and would provide a simplified way to heterostructure-based photodetectors with high-responsivity and fast-speed performances. KEYWORDS: group I−III−VI 2 semiconductor, chalcopyrite-type telluride, monodisperse AgInTe 2 nanocrystals for broadband photodetection, AgInTe 2 -based photodetector, fast-response photodetector
Broadband optoelectronic devices intrigue enormous interests on account of their promising potential in optical communications, sensors and environmental monitoring. PbSe nanocrystals are promising candidates for the construction of next-generation photodetectors due to their fascinating intrinsic properties and solution-processed compatibility with varied substrates. Here, we report the fabrication of a broadband photodetector on the basis of high-quality solution-processed PbSe nanorods in rock-salt phase grown along unconventionally anisotropic growth direction of <112> zone axis. The rock-salt PbSe nanorods are synthesized in solution phase over the catalysis of Ag 2 Se with relatively high-temperature body-centered cubic phase via a solution-solid-solid growth regime using oleylamine and oleic acid as solvents and stabilizer surfactants, from which the PbSe nanorods with the unconventionally anisotropic growth direction are controllably grown in size and shape in the synthetic procedure typically with about 17 nm in diameter and 58 nm in length on average. Meanwhile, the PbSe nanorods-based photodetector exhibits a broadband response from 405 to 1,064 nm with a high responsivity of 0.78 A•W −1 and a fast response time of 17.5 µs. The response time is much faster in comparison with most of the PbSe-based photodetectors with response time in millisecond level.
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