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Purcell effect enhancement of spontaneous emission rates is demonstrated for isoelectronic trap single-photon emitters. Two-dimensional photonic crystal slabs with L3 defects were fabricated in nitrogen delta-doped GaAs. Photoluminescence spectra of each photonic crystal cavity had a series of sharp and bright lines arising from individual nitrogen luminescence centers, which was confirmed by Hanbury-Brown and Twiss measurements. The emission rates of these lines depended on cavity detuning, indicating a resonant character of the enhancement. The observed emission lifetime in the cavity was 400 ps, which would be the shortest lifetime reported so far for luminescence centers in GaAs.

Morphologies and tensile properties of polybutene-1 (PB), PB/fibrous cellulose (FC), and the PB/silanized FC with 3-aminopropyltrimethoxysilane (APTMS) composites were studied. The scanning electron microscope micrographs exhibited the adherent PB parts on the FC and the silanized FC, suggesting that there was a certain affinity of PB to them. The spherulite observation suggested that there existed a secondary bonding between the PB and the FC or the silanized FC. These tensile properties were remarkably affected by the PB crystal phase transformation from the metastable tetragonal (II) to the stable hexagonal (I) phase. The transformation caused the ageing embrittlement even at r.t. In particular, the ageing embrittlement rate of the PB/silanized FC was much higher than other samples. Because the silanized FC became the excellent nucleating agent for the PB crystallization, the PB/silanized FC was found to easily form the thicker lamella having a higher probability of containing a crystal defect to serve as a starting point of the transformation. The higher transformation rate depended on the thicker lamella formation rate and its amount.

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