Enhanced Field Emission from Metallic Surfaces and Nanowires
BeschreibungThe role of material properties, surface preparation and cleaning techniques on Nb and Cu was studied for EFE , which is disastrous for high field vacuum devices. Dry ice cleaning is found to suppress EFE from the metallic surfaces very efficiently. High purity single crystal and large grain Nb samples showed the onset of FE at high fields (120 ? 200 MV/m).
For the first time, the grain boundary assisted field emission was observed for Nb. A correlation
between size of emitters and onset fields is obtained, which sets a threshold for the tolerable defect size to achieve the envisaged accelerating gradients in cavities reliably.
Additionaly, the systematic study performed on electrochemically deposited Cu, Ni and Au nanowires of different aspect ratios and spatial distribution for cold cathode applications. In our findings, Au coating on Ni nanowires provided improved FE properties. Further, in Au Nanowires up to 40 % percentage of the wires were emitting. Achieving much larger emitter number densities ~10^5 cm^?2 at 6 V/µm compared to CNT cathodes with respect to the number of deposited nanostructures, makes Au NWs interesting for cold cathode applications.
PortraitArti Dangwal born in Pauri Garhwal, Uttarakhand, India, is M.Sc. in Physics and M.Tech. in Solid State materials (IIT Delhi). She was awarded by the MHRD scholarship and Junior research fellowship (CSIR) in India. In 2007, she received Ph.D. in Physics from University of Wuppertal, where she worked as a research scientist for DESY Hamburg, Germany.
Untertitel: Paperback. Sprache: Englisch.
Verlag: VDM Verlag
Erscheinungsdatum: Mai 2008
Seitenanzahl: 140 Seiten