Localization Effect in Photoelectron Transport Induced by Alloy Disorder in Nitride Semiconductor Compounds.

Near-band-gap photoemission spectroscopy experiments were performed on p-GaN and p-InGaN/GaN photocathodes activated to negative electron affinity. The photoemission quantum yield of the InGaN samples with more than 5% of indium drops by more than 1 order of magnitude when the temperature is decreased while it remains constant for lower indium content. This drop is attributed to a freezing of photoelectron transport in p-InGaN due to electron localization in the fluctuating potential induced by the alloy disorder.

Violet semipolar (20-2-1) InGaN microcavity light-emitting diode with a 200 nm ultra-short cavity length.

Violet semipolar (20-2-1) InGaN microcavity light-emitting diodes (MC-LED) with a 200 nm ultra-short cavity length were demonstrated. The emission wavelength was 419 nm with a spectrum width of 20 nm. The external quantum efficiency (EQE) of MC-LED was constant at 0.

Universality of fold-encoded localized vibrations in enzymes.

Enzymes speed up biochemical reactions at the core of life by as much as 15 orders of magnitude. Yet, despite considerable advances, the fine dynamical determinants at the microscopic level of their catalytic proficiency are still elusive. In this work, we use a powerful mathematical approach to show that rate-promoting vibrations in the picosecond range, specifically encoded in the 3D protein structure, are localized vibrations optimally coupled to the chemical reaction coordinates at the active site.

Prospects for 100% wall-plug efficient III-nitride LEDs.

The possibility of a III-nitride LED with 100% or greater wall-plug efficiency is examined considering recent observations of the phenomenon for smaller bandgap mid-IR LEDs under extremely low-bias operation [Phys. Rev. Lett.

Stable, Heat-Conducting Phosphor Composites for High-Power Laser Lighting.

Solid-state lighting using laser diodes is an exciting new development that requires new phosphor geometries to handle the greater light fluxes involved. The greater flux from the source results in more conversion and therefore more conversion loss in the phosphor, which generates self-heating, surpassing the stability of current encapsulation strategies used for light-emitting diodes, usually based on silicones. Here, we present a rapid method using spark plasma sintering (SPS) for preparing ceramic phosphor composites of the canonical yellow-emitting phosphor Ce-doped yttrium aluminum garnet (Ce:YAG) combined with a chemically compatible and thermally stable oxide, α-AlO.