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The experimental results of field-emission characteristics of selectively grown randomly oriented multiwalled carbon nanotubes (CNTs) are presented. The CNTs are synthesized onto plain silicon (n-type 100) substrates having an iron (Fe) catalyst layer using chemical vapor deposition. The field-emission measurement results indicate that the randomly oriented CNTs have significant field-emission capabilities, and the pattern size has an impact on the effective emission area. Effects of pattern size on the turn-on field of the samples are investigated. [ABSTRACT FROM AUTHOR]

Pseudospark switches are fast-closing low-pressure gas discharge switches with a hollow-cathode geometry. They can be triggered optically or by electron injection, where electrons emitted from a cold cathode emitter are accelerated in the electric field and initiate breakdown. The efficiency of charge carrier accumulation in the hollow-cathode structure determines the performance of the switch operation. The advantages of such switches include high hold-off voltage, high conduction current, fast current rise time, low delay and jitter time, and long lifetime. In this paper, the operating characteristics of a pseudospark switch, triggered by a carbon-nanotube (CNT)-coated electron emitter, are presented. The electron emitter is fabricated by coating randomly oriented CNTs on silicon substrate using chemical vapor deposition method. Field emission characteristics of CNTs are determined and then used as part of the trigger electrode which is integrated into an in-house constructed pseudospark switch. The operating characteristics of the switch are tested under different background pressures and different trigger voltages. Delay and jitter time under different working conditions are analyzed. Hold-off voltage and current rise time are also presented. [ABSTRACT FROM PUBLISHER]