The Study Of CdTe Quantum Dots Fluorescence Enhancement Affected By Gold Nanoholes Array

Surface-enhanced fluorescence (SEF) is a hot research topic now. When fluorescentmaterials are close to the surface of metal, the fluorescence is enhanced due to the local fieldenhancement. Precious metals receive special attention because they are hard to be oxidizedand the surface plasmon resonance falls in the visible spectrum. We can change thedistribution of electric field near the surface of metal through designing its nano-structure.Quantum dots (QDs) are fluorescent materials whose emitting character is in the control oftheir size and widely applied in energy, biomedicine, information and sense field. It isnecessary to explore the influence of QDs’ fluorescence interacting with precious metal intheory and application. In this thesis, we focus on gold nanoholes array (GNHA) and CdTeQDs.Nanosphere lithography (NSL) is proved to be an economical and efficientnanofabrication technique. Here we use this method to produce the mask which is a singlelayer of self-assembled nanospheres. In order to get GNHA, we firstly etch the mask in themethod of refractive ion etching (RIE), then deposit gold via pulsed laser deposition (PLD),and finally remove the mask. In order to research the interacting between CdTe QDs andGNHA, we produce a layer of CdTe QDs with the polyvinyl alcohol (PVA) solution in themethod of spin-coating upon the GNHA.We test the light transmission of GNHA and calculate it in finite-differencetime-domain (FDTD) method to study surface plasmon polarizations (SPPs) and localizedsurface plasmon resonance (LSPR) affected by GNHA. We find that the simulative resultsagree well with the experimental ones.The CdTe QDs’ fluorescence enhanced by GNHA is studied in Confocal fluorescencespectrum method. We discuss the enhancement effect in4situations: QDs of differentfluorescent spectrum, excitation light of different wavelength, nanoholes of different radioand original and annealing GNHAs. It is obvious that GNHA can enhance the fluorescenceof QDs through comparing the samples of QDs with and without GNHA respectively. The conclusion is that the fluorescence enhancement of QDs is affected of localized fieldenhancement and absorption of GNHA. When fluorescent spectrum is far away fromabsorption peak and the wavelength of excitation light is close to transmission peak, theenhancement factor reaches its maximum.