Nanoscale AgInTe2/Si Truncated Quasitetrahedrons for Heterostructured Photodetectors

Group I-III -VI2 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 AgInTe2 nanostructures have been synthesized via a facilely designed solution-phase procedure at 240-280 degrees C from AgNO3 and In(acac) 3 in oleylamine reacted with TeO2 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 AgInTe2/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 X 10(11) Jones), and a low noise equivalent power (2.46 X 10(-13) W Hz(-)(1/)(2)) at a bias of -2 V. Especially, the device exhibits fast response speeds (tau(rise) = 5.2 mu s, tau(fall) = 18.4 mu s), 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 AgInTe2 nanostructures and would provide a simplified way to heterostructure-based photodetectors with high-responsivity and fast-speed performances.