Tokyo University of Science

About: Tokyo University of Science is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Thin film & Enantioselective synthesis. The organization has 15800 authors who have published 24147 publications receiving 438081 citations. The organization is also known as: Tōkyō Rika Daigaku & Science University of Tokyo.

Emission mechanisms of bulk GaN and InGaN quantum wells prepared by lateral epitaxial overgrowth

Abstract: The emission mechanisms of bulk GaN and InGaN quantum wells (QWs) were studied by comparing their optical properties as a function of threading dislocation (TD) density, which was controlled by lateral epitaxial overgrowth Slightly improved excitonic photoluminescence (PL) intensity was recognized by reducing TD density from 1010 cm−2 to less than 106 cm−2 However, the major PL decay time was independent of the TD density, but was rather sensitive to the interface quality or material purity These results suggest that TDs simply reduce the net volume of light-emitting area This effect is less pronounced in InGaN QWs where carriers are effectively localized at certain quantum disk size potential minima to form quantized excitons before being trapped in nonradiative pathways, resulting in a slow decay time The absence of any change in the optical properties due to reduction of TD density suggested that the effective band gap fluctuation in InGaN QWs is not related to TDs

Inorganic nanoparticles for optical bioimaging

Abstract: The tremendous progress in the synthesis of different inorganic nanoparticles with pretailored size, shape, structural, compositional, and surface properties has significantly raised their potential applications in biomedicine. Optically active inorganic nanoparticles are those that, based on inorganic materials, can produce fluorescence or scattered light under suitable optical excitation. These outgoing radiations can be conveniently used for bioimaging purposes. In this work, the different types of optically active inorganic nanoparticles that are being used for optical bioimaging are reviewed in detail. Special attention is paid to fluorescent and inorganic persistent luminescence nanoparticles and how their different excitation mechanisms (no-photon, one-photon, or multiphoton excited fluorescence) and working spectral ranges can be conveniently applied for in vitro and in vivo high-contrast optical bioimaging.