White Electroluminescence Using ZnO Nanotubes/GaN Heterostructure Light-Emitting Diode

We report the fabrication of heterostructure white light–emitting diode (LED) comprised of n-ZnO nanotubes (NTs) aqueous chemically synthesized on p-GaN substrate. Room temperature electroluminescence (EL) of the LED demonstrates strong broadband white emission spectrum consisting of predominating peak centred at 560 nm and relatively weak violet–blue emission peak at 450 nm under forward bias. The broadband EL emission covering the whole visible spectrum has been attributed to the large surface area and high surface states of ZnO NTs produced during the etching process. In addition, comparison of the EL emission colour quality shows that ZnO nanotubes have much better quality than that of the ZnO nanorods. The colour-rendering index of the white light obtained from the nanotubes was 87, while the nanorods-based LED emit yellowish colour

Photolumniscence/Fluorescence Spectroscopic Technique for Nanomaterials Characterizations

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Influence of silver film quality on the threshold of plasmonic nanowire lasers

Plasmonic nanowire lasers are nanoscopic sources of light operating at deep subwavelength scales with ultrafast dynamics.[1-6] Such lasers enable the investigation of enhanced light-matter interactions and can have large impact on applications in the fields of non-linear optics, sensing, and optical communications.[7-12] However, metal-based lasers suffer from high losses, caused by the inherent electron scattering in metals, which leads to an increased lasing threshold and limits their use in applications. To minimise losses and thus improve their performance, it has been suggested to use metal films of high quality which ideally have an ultra-flat surface with a high crystalline perfection.[1, 13-16] However, investigating the effects of Ag film quality on the performance of hybrid-plasmonic zinc oxide (ZnO) nanowire lasers this work finds that such a laser geometry is dominated by losses in the gain material