[en] Tapered dielectric structures in metal have exhibited extraordinary performance in both surface plasmon polariton (SPP) waveguiding and SPP focusing. This is crucial to plasmonic research and industrial plasmonic device integration. We present a method that facilitates easy fabrication of smooth-surfaced sub-micron tapered structures in large scale simply with electron beam lithography (EBL). When a PMMA layer is spin-coated on previously-EBL-defined PMMA structures, steep edges can be transformed into a declining slope to form tapered PMMA structures, scaled from 10 nm to 1000 nm. Despite the simplicity of our method, patterns with PMMA surface smoothness can be well-positioned and replicated in large numbers, which therefore gives scientists easy access to research on the properties of tapered structures. (cross-disciplinary physics and related areas of science and technology)

[en] GaN nanowires doped with 2at.% and 6at.% Cu ions are synthesized by chemical vapour deposition method. Structural and compositional analyses demonstrate that the as-grown nanowires are of single crystal wurtzite GaN structure. Magnetic characterizations reveal that the doped GaN nanowires exhibit room temperature ferromagnetism. The measured saturation magnetic moments are 0.37μB and 0.47μB per Cu atom at 300K for Cu 2at.% and 6at.%, respectively. The photoluminescence spectra show that Cu dopant can tune the band gap of the GaN, which leads to a red shift of band-edge emission with increasing dopant concentration. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

[en] Vibration responses were investigated for a viscoelastic Single-walled carbon nanotube (visco-SWCNT) resting on a viscoelastic foundation. Based on the nonlocal Euler-Bernoulli beam model, velocity-dependent external damping and Kelvin viscoelastic foundation model, the governing equations were derived. The Transfer function method (TFM) was then used to compute the natural frequencies for general boundary conditions and foundations. In particular, the exact analytical expressions of both complex natural frequencies and critical viscoelastic parameters were obtained for the Kelvin-Voigt visco-SWCNTs with full foundations and certain boundary conditions, and several physically intuitive special cases were discussed. Substantial nonlocal effects, the influence of geometric and physical parameters of the SWCNT and the viscoelastic foundation were observed for the natural frequencies of the supported SWCNTs. The study demonstrates the efficiency and robustness of the developed model for the vibration of the visco-SWCNT-viscoelastic foundation coupling system