Search results for "nanofysiikka"
showing 6 items of 6 documents
Surface plasmon effects on carbon nanotube field effect transistors
2011
Herein, we experimentally demonstrate surface plasmon polariton (SPP) induced changes in the conductivity of a carbon nanotube field effect transistor (CNT FET). SPP excitation is done via Kretschmann configuration while the measured CNT FET is situated on the opposite side of the metal layer away from the laser, but within reach of the launched SPPs. We observe a shift of 0.4 V in effective gate voltage. SPP-intermediated desorption of physisorbed oxygen from the device is discussed as a likely explanation of the observed effect. This effect is visible even at low SPP intensities and within a near-infrared range. peerReviewed
Quantum size effect in low dimensional bismuth nanostructures
2009
Annealing study of bismuth thin films
2010
Electrical and magnetotransport properties of thin bismuth films were studied in the range of 4.2 - 295 K in applied magnetic fields up to 3.5 T. The bismuth films were deposited on mica and SiO substrates and subjected to post deposition thermal annealing in order to improve the crystal structure. Annealed films showed lower resistivities and higher magnetoresistance as compared to the non annealed samples, however, the resistivity behavior was non-metallic and the mean grain size in the films were not significantly increased. A two carrier model for magnetoresistance and Hall coefficient was used to extract carrier mobilities and concentrations from the transport data.
Experimental study of quantum fluctuations in titanium nanowires in highly resistive environment
2009
Development of niobium-based superconducting junctions
2012
This thesis presents a review of publications which mainly focuses on the fabrication and performance of Nb-based normal metal-insulator-superconductor (NIS) tunnel junctions and superconductor-normal metal-superconductor (SNS) Josephson junctions at low temperatures. The Cu/AlOx-Al/Nb based NIS double tunnel junctions were successfully fabricated using conventional electron beam lithography combined with multi-angle thermal evaporation of metals in ultra high vacuum. The subgap characteristics of these junctions showed expected temperature dependence from 0.2 K to 5 K with a good thermometry sensitivity 0.2-0.3 mV/K. Signatures of small electronic cooling effects were observed near the Nb …