AUTOELECTRONIC CATHODES BASED ON ARRAYS OF NIOBIUM-OXIDE COLUMNAR NANOSTRUCTURES FOR FIELD EMISSION DISPLAYS

Abstract

The article discusses the prospects of creating controlled field-effect cathodes based on arrays of columnar oxide niobium nanostructures for field emission displays. Geometrical models of field-emission cathodes and vacuum elements have been developed and investigated. The distribution of the electric field in the vacuum device at various distances between the cathode and the anode, the applied voltages between them, the shape and microgeometry of the cathodes were obtained. The optimal geometric parameters of nanostructured autoelectronic cathodes and matrices of these were calculated based on the simulation. The technological route has been developed for the production of autoelectronic cathode matrices based on arrays of niobium-oxide columnar nanostructures formed by electrochemical anodization of Al/Nb thin-film system. The samples of controlled arrays of autoelectronic cathodes were fabricated and the current-voltage characteristics with interelectrode gap of 2, 5 and 10 μm in various electric modes with change in the electric field strength from 3 to 85 V/μm were studied. At 2 μm gap between the anode and cathode, the emission occurs at minimum threshold voltages, but it is characterized by limited current values. The increasing in the interelectrode gap allows rising the emission currents, however, the threshold voltages increase. In the pulsed mode, the large emission currents are achieved. The threshold voltage of autoelectronic cathode matrices with interelectrode gap of 5 μm was 9.16 V, the maximum currents reached 350 μA at voltage of 22.5 V. In the pulsed mode, the emission arose at 11.06 V, the maximum current reached 1500 μA at 40 V.