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A ridge‐shaped AlGaInP/GaInP quantum well (QW) structure with a ridge top width in the sub‐wavelength region (500–600 nm) is successfully fabricated by selective area metal organic vapor phase epitaxial growth on patterned GaAs substrates, as the first step towards the realization of high‐efficiency light‐emitting diodes (LEDs) utilizing the evanescent wave coupling effect. It is confirmed by an X‐ray diffraction study that AlGaInP layers grown on all the different facets of the ridge structure satisfy the lattice matching requirements for high‐efficiency LED applications. A considerable enhancement of the light‐extraction efficiency in the fabricated ridge‐shaped QW structure is demonstrated by means of a photoluminescence analysis. The realization of the evanescent wave coupling effect is suggested by theoretical simulation. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Hydrogen absorptions of LaFe 11.5 Si 1.5 compound in 1-atm hydrogen gas at different temperatures are investigated. The hydrogen content in the hydrogenated sample does not increase with the increase of temperature of hydrogen absorption but changes complicatedly. The characteristic of first-order transition in LaFe 11.5 Si 1.5 compound is weakened after hydrogen absorption. It leads the peaks of magnetic entropy to become wider and the hysteresis loss to reduce significantly, but relative cooling power (RCP) is not changed considerably.