An official website of the United States government
We demonstrate a low-temperature synthesis of ultrasmall (<2 nm) HgTe quantum dots (QDs) with superlative optical properties in the near and shortwave infrared. The tunable cold-injection synthesis produces HgTe QDs ranging from 1.7 to 2.3 nm in diameter, with photoluminescence maxima ranging from 900 to 1180 nm and a full-width at half-maximum of ∼100 nm (∼130 meV). The synthesized quantum dots display high photoluminescence quantum yields (PLQY) ranging from 80 to 95% based on both relative and absolute methods. Furthermore, samples retain their high PLQY (∼60%) in the solid state, allowing for first-of-their-kind photoluminescence imaging and blinking studies of HgTe QDs. The facile synthesis allows for the isolation of small, photostable HgTe quantum dots, which can provide valuable insight into the extremes of quantum confinement.
more »
« less
This content will become publicly available on June 16, 2026
Branched HgTe Nanorods for Stable Room Temperature Extended Short-Wave Infrared Photodetectors
Single-element detectors (SEDs) with a room temperature extended short-wave infrared (eSWIR) photoresponse were fabricated with branched nanorods of HgTe. Nanorods with high aspect (length/width) ratios were obtained by using stoichiometric excesses of Hg (i.e., [Hg]/[Te] molar ratios greater than one) and relatively low reaction temperatures, as low as room temperature. The size-tunable optical cutoff wavelengths of the detectors ranged from 2 to 3.5 μm, with specific detectivities as high as 2.4 × 10^11 Jones. The devices retained their responsivity for more than a year. Branched nanorods of HgTe are promising materials for IR photodetectors and imagers.
more »
« less
- Award ID(s):
- 2052814
- PAR ID:
- 10610980
- Publisher / Repository:
- ACS Nano
- Date Published:
- Journal Name:
- ACS Nano
- ISSN:
- 1936-0851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
null (Ed.)A highly porous adsorbent based on a metal–organic framework was successfully designed and applied as an innovative adsorbent in the solid phase for the heavy metal removal. MIL-125 was densely decorated by 2-imino-4-thiobiuret functional groups, which generated a green, rapid, and efficacious adsorbent for the uptake of Hg( ii ) and Pb( ii ) from aqueous solutions. ITB-MIL-125 showed a high adsorption affinity toward mercury( ii ) ions of 946.0 mg g −1 due to covalent bond formation with accessible sulfur-based functionality. Different factors were studied, such as the initial concentration, pH, contact time, and competitive ions, under same circumstances at the room temperature. Moreover, the experimental adsorption data were in excellent agreement with the Langmuir adsorption isotherm and pseudo-second order kinetics. At a high concentration of 100 ppm mixture of six metals, ITB-MIL-125 exhibited a high adsorption capacity, reaching more than 82% of Hg( ii ) compared to 62%, 30%, 2%, 1.9%, and 1.6% for Pb( ii ), Cu( ii ), Cd( ii ), Ni( ii ), and Zn( ii ), respectively.more » « less
-
Cadmium zinc telluride selenide (CdZnTeSe) is emerging as a promising semiconductor material for low-cost production of nuclear and radiological detection systems capable of operating at room temperature. This paper presents studies of the fabrication process and detector response for gamma-ray detectors produced from high-quality CdZnTeSe crystals grown by the traveler heater method (THM). The resistivity of the CdZnTeSe is on the order of 10 GΩ-cm. The electron mobility-lifetime (μτ) product characterizing the charge-transport properties is on the order of 0.001 square-cm per volt. Energy resolutions as good as 6.5% FWHM for the 59.5-keV gamma-peak of 241 Am were recorded for planar detectors with gold contacts.more » « less
-
The sensitivity of gravitational-wave detectors is limited by the mechanical loss associated with the amorphous coatings of the detectors’ mirrors. Amorphous silicon has higher refraction index and lower mechanical loss than current high-index coatings, but its optical absorption at the wavelength used for the detectors is at present large. The addition of hydrogen to the amorphous silicon network reduces both optical absorption and mechanical loss for films prepared under a range of conditions at all measured wavelengths and temperatures, with a particularly large effect on films grown at room temperature. The uptake of hydrogen is greatest in the films grown at room temperature, but still below 1.5 at.% H, which show an ultralow optical absorption (below 10 ppm) measured at 2000 nm for 500-nm-thick films. These results show that hydrogenation is a promising strategy to reduce both optical absorption and mechanical loss in amorphous silicon, and may enable fabrication of mirror coatings for gravitational-wave detectors with improved sensitivity.more » « less
-
We present mid-IR spectroscopic characterization of the low-phonon chalcogenide glass, Ga2Ge5S13 (GGS) doped with Er3+ ions. Under the excitation at ∼800 nm, Er3+:GGS exhibited broad mid-IR emission bands centered at ∼2.7, ∼3.5, and ∼4.5 µm at room temperature. The emission lifetime of the 4I9/2 level of Er3+ ions in GGS glass was found to be millisecond-long at room temperature. The measured fluorescence lifetimes were nearly independent of temperature, indicating negligibly small nonradiative decay rate for the 4I9/2 state, as can be expected for a low-maximum-phonon energy host. The transition line-strengths, radiative lifetimes, fluorescence branching ratios were calculated by using the Judd-Ofelt method. The peak stimulated emission cross-section of the 4I9/2 → 4I11/2 transition of Er3+ ion was determined to be ∼0.10×10−20 cm2 at room temperature.more » « less
