Current Issue : July - September Volume : 2015 Issue Number : 3 Articles : 4 Articles
By using a homojunction-structured GaP single crystal, we generated a photon energy higher than the bandgap energy (2.26 eV).\nThe device was fabricated by performing dressed-photon-phonon- (DPP-) assisted annealing, while applying a forward-bias\ncurrent, on a p-n homojunction structure formed by implanting a dopant (Zn) into an n-type GaP substrate. The DPP-assisted\nannealing increased the light emission intensity in an energy band above 2.32 eV by at least 550% compared with that before\nannealing....
We compared dressed-photon-phonon (DPP) etching to conventional photochemical etching and, using a numerical analysis of\ntopographic images of the resultant etched polymethyl methacrylate (PMMA) substrate, we determined that the DPP etching\nresulted in the selective etching of smaller scale structures in comparison with the conventional photochemical etching. We\ninvestigated the wavelength dependence of the PMMA substrate etching using an O2 gas. As the dissociation energy of O2 is\n5.12 eV, we applied a continuous-wave (CW) He-Cd laser (? = 325 nm, 3.81 eV) for the DPP etching and a 5th-harmonic Nd:YAG\nlaser (? = 213 nm, 5.82 eV) for the conventional photochemical etching. From the obtained atomic force microscope images, we\nconfirmed a reduction in surface roughness, R\na, in both cases. However, based on calculations involving the standard deviation of\nthe height difference function, we confirmed that the conventional photochemical etchingmethod etched the larger scale structures\nonly, while the DPP etching process selectively etched the smaller scale features...
We propose a robust method to distinguish isolated single gold nanoparticles (AuNP monomers) and their dimers under Brownian\nmotion, a key for ultrasensitive homogeneous bioassays, including AuNP sandwich assays. To detect dimers and distinguish them\nfrom a larger number of monomers in aqueous solution, single-particle polarization microscopy was performed. For the accurate\ndetection of individual particles, the optical anisotropy and rotational diffusion time are measured because a dimer is much more\nanisotropic than the nearly spherical monomer and the rotational diffusion time of a dimer is four times that of a monomer.\nBy employing an autocorrelation analysis, we defined a measure of distinguishing that simultaneously enables high detection\nprobability and low error probability.The detection platform offers homogeneous DNA hybridization assays and immunoassays at\nthe subpicomolar level....
We investigate the modulation of the localized surface plasmon resonance (LSPR) of a gold nanorod (AuNR) using a GeSbTe film\nas an active medium. We demonstrate high-contrast switching of LSPR in an AuNR/GST/Au thin film sandwich structure upon\nphase change. To go beyond this single-particle switching functionality, we consider a plasmon particle system interacting with\na phase-change material (PCM) to discuss the possibility of parallel processing devices with memory functionality, exploiting the\nplasticity and threshold behavior that are inherent characteristics of PCMs.We demonstrate that the temporal and spatial evolution\nof a plasmon-PCM array system can be equivalent to a cellular automata algorithm....
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