Visible and near-IR photoluminescence (PL) is reported from sub-10 nm silicon nanopillars. Pillars were plasma etched from single crystal Si wafers and thinned by utilizing strain-induced, self-terminating oxidation of cylindrical structures. PL, lifetime, and transmission electron microscopy were performed to measure the dimensions and emission characteristics of the pillars. The peak PL energy was found to blue shift with narrowing pillar diameter in accordance with a quantum confinement effect. The blue shift was quantified using a tight binding method simulation that incorporated the strain induced by the thermal oxidation process. These pillars show promise as possible complementary metal oxide semiconductor compatible silicon devices in the form of light-emitting diode or laser structures.
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Food Res Int
February 2025
Izmir Institute of Technology, Department of Food Engineering, Urla-Izmir, Turkiye. Electronic address:
The detection of adulteration in apple juice concentrate is critical for ensuring product authenticity and consumer safety. This study evaluates the effectiveness of artificial neural networks (ANN) and support vector machines (SVM) in analyzing spectroscopic data to detect adulteration in apple juice concentrate. Four techniques-UV-visible, fluorescence, near-infrared (NIR) spectroscopy, and time domain H nuclear magnetic resonance relaxometry (H NMR)-were used to generate data from both authentic and adulterated apple juice samples.
View Article and Find Full Text PDFHere we report a simple self-masking technique for fabricating bioinspired broadband antireflection coatings on both single-crystalline and multicrystalline silicon wafers with the assistance of a polyimide tape. Subwavelength-structured moth-eye nanopillars, which exhibit superior antireflection performance over a broad range of visible and near-IR wavelengths, can be patterned uniformly on the wafer surface by applying a chlorine-based reactive ion etching (RIE) process. The resulting random nanopillars show improved antireflection properties compared with ordered nanopillars templated by colloidal lithography under the same RIE conditions.
View Article and Find Full Text PDFNanoscale Horiz
January 2025
Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Upconverting nanoparticles (UCNPs) convert near-infrared (IR) light into higher-energy visible light, allowing them to be used in applications such as biological imaging, nano-thermometry, and photodetection. It is well known that the upconversion luminescent efficiency of UCNPs can be enhanced by using a host material with low phonon energies, but the use of low-vibrational-energy inorganic ligands and non-epitaxial shells has been relatively underexplored. Here, we investigate the functionalization of lanthanide-doped NaYF UCNPs with low-vibrational-energy SnS ligands.
View Article and Find Full Text PDFMicromodification in bulk undoped polymethylmethacrylate (PMMA) by single focused (numerical aperture (NA) = 0.25), 1030-nm 250-fs laser pump pulses was explored by pump self-transmittance; optical, 3D-scanning confocal photoluminescence (PL); Raman micro-spectroscopy; and optical polarimetric and interferometric microscopy. Starting from the threshold pulse energy = 0.
View Article and Find Full Text PDFInorg Chem
December 2024
Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Bldg 4, 31 Leninsky Prosp., Moscow 119071, Russian Federation.
Four new Np(V) perchlorate complexes of the composition [NpO(HO)]ClO (orthorhombic) (), [(NpO)(ClO)(HO)]ClO·HO (), [(NpO)(UO)(HO)](ClO) (), and [(NpO)Cl(HO)]ClO·2HO () have been synthesized and structurally characterized. The structure of previously known monoclinic modification of NpOClO·4HO () has been determined at 100 K. The coordination environment of Np and U atoms in compounds - is pentagonal bipyramids.
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