Si-Based GaN Light-Emitting Diodes with MoS₂ Nanosheet-Decorated Fabry–Perot Waveguide Structure

Abstract

III−V semiconductor light-emitting diodes (LEDs) on Si substrates, suitable for large-scale and large-wafer-size manufacturing, are a convenient option for on-chip light sources. Here, we present the design and fabrication of a MoS 2 nanosheetdecorated InGaN/AlGaN/GaN LED on a Si substrate with a Fabry−Perot waveguide, utilizing standard microfabrication processes. We assess the voltage−current characteristics, electroluminescence (EL) properties, polarization properties, chrominance, and surface temperature of the device. The MoS 2 layer's spectrum filtering effect and the waveguide's interference effect influence the EL properties of GaN LED. The MoS 2 -decorated LED device presented different properties than the bare LED in terms of a higher turn-on voltage, uniform emission pattern, lower surface temperature, and higher polarizability. Besides, the underlying mechanism for spectral modulation is studied. The MoS 2decorated device demonstrates an EL peak near 417 nm, with a high side mode suppression ratio and full width at half-maximum (FWHM) < 1 nm. Our study offers insights into the potential realization of light sources with narrowed spectra using GaN LEDs based on Si materials.

Ligand-Induced Red-Emitting Copper Nanoclusters for Selective Fluorescence Determination of Aluminum Ions

“…Copper nanoclusters (CuNCs) are sized to match the Fermi wavelength of electrons, showing promise in environmental sensing applications. − CuNCs exhibit the ability to detect a wide range of targets, from ions to macromolecules, allowing for real-time water quality monitoring due to their high quantum yield, dispersibility in water, and stability in the presence of salt. , Most of the fluorescence sensing mechanisms involved in CuNCs are fluorescence turn-off mechanism, which may include an internal filtering effect, static quenching, aggregation-induced quenching, etc. However, an unexpected phenomenon known as aggregation-induced emission (AIE) has been observed in organic systems, enhancing the emission efficiency and fluorescence intensity of CuNCs by restricting intramolecular motion. , These unique fluorescence properties make CuNCs valuable in applications like optical imaging, as well as enabling sensitive detection in complex environments using smartphone-based sensors. − …”