|
|
Graphene photodetector based on plasmonic effects
Horáček, Matěj ; Hájková,, Zdenka (referee) ; Šikola, Tomáš (advisor)
Two rich and vibrant fields of investigation - graphene and plasmonics - strongly overlap in this work, giving rise to a novel hybrid photodetection device. The intrinsic photoresponse of graphene is significantly enhanced by placing the gold nanorods exhibiting unique anisotropic localized surface plasmon resonances on the graphene surface. The reported enhanced photoresponse of graphene is caused by the redistribution of localized surface plasmons in the nanoparticles into graphene. The exact underlying energy redistribution mechanism is thoroughly studied by a single particle scattering spectroscopy monitoring the particle plasmon linewidth as a function of the number of underlaying graphene layers. The obtained extraordinary plasmon broadening for nanoparticles placed on graphene suggests the contribution of a novel energy redistribution channel attributed to the injection of hot electrons from gold nanorods into graphene.
|
|
|
Fabrication of well defined nanoporous structures with application in membrane sensing
Fabianová, Kateřina ; Édes, Zoltán (referee) ; Sadílek, Jakub (advisor)
Theme of this bachelor thesis is focused on preparation of the metal nanomenhir structures situated in highly oriented matrix of silicon nitride nanopores based plasmonic biosensor. Porous structures were prepared by reactive ion etching of silicon nitride film using electron beam lithography prepared temporary mask as a template. Deposition of metals was handled by evaporation and magnetron sputtering and results was compared. Finally, this work assumes reached results including successful approach of sensor preparation without contamination of surrounding surface by heavy metal ions.
|
|
|
Vliv teploty na plazmonické vlastnosti nanočástic
VOBRUBA, Jan
Nanoparticle-based thin films find the utilization in a wide range of applications, based on the unique properties of these nano-objects. If the metal nanoparticle is illuminated by the light with the correct wavelength, collective oscillations of electrons can be excited in the nanoparticle, which leads either to an enormous increase of electrical intensity near the nanoparticle and to significant optical absorption at a given wavelength. This phenomenon of localized surface plasmon resonance (LSPR) strongly depends on the material, shape, and amount of nanoparticles, but also on the optical properties of the surrounding environment. Nanoparticle surfaces can thus be used for the preparation of LSPR sensors or substrates for surface-enhanced Raman spectroscopy. In this work, silver nanoparticle films were prepared by magnetron sputtering, where a very small amount of material was deposited on the glass substrate, which resulted in the formation of nano-islands. The influence of deposition conditions on the optical properties of the resulting layers was studied. It is shown that both the depth of the LSPR peak and its position can be changed by variation of the deposition time and the heating temperature.
|
|
|
Solid-state Synthesis of Gold Nanoparticles on Dimpled Aluminum Surfaces and Their Transfer to Transparent Substrates
Lednický, Tomáš
In this work, it is proposed a novel and cost-effective fabrication method for forming gold nanoparticle films on transparent substrates. The method involves fabrication of templated aluminium substrate by porous-type anodic oxidation of aluminium foils. Furthermore, a thin gold layer is deposited over and subsequently annealed which results into the gold nanoparticles formation. Additionally, it is proposed a transfer onto transparent substrates such as PDMS or PMMA. The goal of this research is to build a localized surface plasmon resonance (LSPR) sensor element with a high performance and low fabrication costs.
|
|
|
Fabrication of well defined nanoporous structures with application in membrane sensing
Fabianová, Kateřina ; Édes, Zoltán (referee) ; Sadílek, Jakub (advisor)
Theme of this bachelor thesis is focused on preparation of the metal nanomenhir structures situated in highly oriented matrix of silicon nitride nanopores based plasmonic biosensor. Porous structures were prepared by reactive ion etching of silicon nitride film using electron beam lithography prepared temporary mask as a template. Deposition of metals was handled by evaporation and magnetron sputtering and results was compared. Finally, this work assumes reached results including successful approach of sensor preparation without contamination of surrounding surface by heavy metal ions.
|
|
|
Graphene photodetector based on plasmonic effects
Horáček, Matěj ; Hájková,, Zdenka (referee) ; Šikola, Tomáš (advisor)
Two rich and vibrant fields of investigation - graphene and plasmonics - strongly overlap in this work, giving rise to a novel hybrid photodetection device. The intrinsic photoresponse of graphene is significantly enhanced by placing the gold nanorods exhibiting unique anisotropic localized surface plasmon resonances on the graphene surface. The reported enhanced photoresponse of graphene is caused by the redistribution of localized surface plasmons in the nanoparticles into graphene. The exact underlying energy redistribution mechanism is thoroughly studied by a single particle scattering spectroscopy monitoring the particle plasmon linewidth as a function of the number of underlaying graphene layers. The obtained extraordinary plasmon broadening for nanoparticles placed on graphene suggests the contribution of a novel energy redistribution channel attributed to the injection of hot electrons from gold nanorods into graphene.
|
guest ::
