Nanoscale AgInTe₂/Si Truncated Quasitetrahedrons for Heterostructured Photodetectors

Abstract

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

Solution-grown ternary quasi-cube AgSbTe2 and its optoelectronic performance for broadband photodetection

“…Another set of doublets located at 576.2 and 586.6 eV can further prove the existence of TeO 2 , which was probably caused by surface oxidation, in good agreement with its frequent occurrence for telluride in previous studies. 25…”

“…Another set of doublets located at 576.2 and 586.6 eV can further prove the existence of TeO 2 , which was probably caused by surface oxidation, in good agreement with its frequent occurrence for telluride in previous studies. 25 To investigate the optoelectronic characteristics of the solution-grown ternary quasi-cube AgSbTe 2 nanostructures, a typical photodetector device was fabricated on a glass substrate with a slit between two adjacent parts of the indium tin oxide film. Fig.…”

“…22 Up to now, there have been few reports on growing phase-pure AgSbTe 2 nanocrystals at relatively low-temperatures without specific equipment probably due to the large atomic diameter and heavy atomic mass of the tellurium atom, thus resulting in inactive chemical reactions in terms of thermodynamics and dynamics. 25 Luckily, Moser et al successfully synthesized small AgSbTe 2 nanostructures at 80 °C with the injection of tri- n -octylphosphine and lithium bis(trimethylsilyl)amide. 26 Nevertheless, the employment of air-unstable and toxic reagents and poorly crystalline products might restrict their application in industrial fields.…”

High-Pressure Structural Transformation Pathway and Electronic Properties of AgGaTe2: Ab Initio Evolutionary Structural Searching

“…I 4̅ 2 d ) IB-IIIA-VIA 2 is a group of ternary semiconductors. Their crystal structures are analogous with a double zinc blende or B3 structure (IIB-IVA) in which IIB atoms are replaced by IB and IIIA atoms with a ratio of 1:1. − It is well-known that the IB-IIIA-VIA 2 compounds have been intensively investigated because of their various applications; for example, CuInSe 2 is a vital absorber layer material and gives an advantage to flexible thin-film solar cells with high conversion efficiencies of approximately 19%. − CuInTe 2 has applications in photoluminescent and photovoltaic devices. , Furthermore, AgInTe 2 could be used for optoelectronic switching at higher frequencies and heterostructure-based photodetectors . More interestingly, numerous recent studies have shown that chalcopyrite compounds potentially exhibit promising thermoelectric (TE) materials with high values of figure of merit (ZT). − Especially in Ag-based chalcopyrite semiconductive materials, the thermal conductivities of AgGaTe 2 and AgInTe 2 are relatively low compared to those of CuGaTe 2 and CuInTe 2 , leading to them being widely studied for application in TE materials. , AgGaTe 2 with varying Ag content has a beneficial ZT of 0.8 at 850 K .…”

Novel solution synthesis of the overlooked cubic phase Cu2GeTe3 nanocrystals for optoelectronic devices

“…Besides, the optical band gap value is calculated by plotting ( αhν ) 2 versus hν ( α = absorption coefficient, h = Planck's constant, and ν = frequency). 39 By extrapolating the linear portion of the plot (the inset in Fig. 4a), a direct optical band gap is determined to be 1.25 eV.…”