Plasmonic metamaterials for luminescent enhancement from quantum dot

• Main Authors: Shen, Tien-Lin, 沈天琳
• Other Authors: Kuo, Hao-Chung
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/ntmb59

碩士 === 國立交通大學 === 光電工程研究所 === 103 === In this thesis, we combine two innovative material: plasmonic metamaterials and semiconductor quantum dots which can be considered as photons and electrons coupling at the microcosmic. Since the excitons and photons are different elementary particle, to finely couple these two kinds of mechanism may face many difficulties. Therefore, we try to control the spontaneous emission of quantum dots by designed plasmonic resonance of metamaterials. First, we analyze the effect of different resonance type from metallic nanostructure on quantum dot emission. We illustrated multiple plasmonic resonances with asymmetric split ring resonantor which offers us several kinds of resoanace. Since the meta-molecule is at the scale of subwavelength and is highly related to the morphology of the fabricated structure. In this study, we fabricate the planar meta-molecule at the feature size of 30 nm and the measured spectra is quite matched to the calculated resonances. Furthermore, to achieve good exciton-plasmon coupling, the magnetic dipole is chosen to match the quantum dot fluorescence wavelength. In short, we successfully propose asymmetric split ring resonator and investigate the enhanced light emission of quantum dot under different kinds of dipole mode which leads us to the following works. We have already informed that the characteristics of magnetic dipole can improve the light emission of quantum dots, therefore, we would like to further enhance quantum dot fluorescence via the structure which is sandwiched with insulator. Owing to the difference of refractive index and surface plasmon, the electric field will be enhanced around the metal surface and inside the insulator layers. We optimized the thickness of the SiO2 and the numbers of the layer, and simulate the stacking metamaterial along with our PbS quantum dots. In summary, the enhancement factor of quantum dot can be furthure improved from 3.5 to 4.5 via stacking metamaterials. Such these results can be applied in optical communication, biosensor, fluorescence imaging, and other novel QD-based optoelectronic devices.