AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Tuesday Sessions
       Session NS-TuP

Paper NS-TuP14
Hydrogen Effects on the Field Emission of Carbon Nanostructures

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Nanometer Scale Science and Technology Poster Session
Presenter: P. Miraldo, College of William & Mary
Authors: P. Miraldo, College of William & Mary
R.A. Outlaw, College of William & Mary
X. Zhao, College of William & Mary
J.J. Wang, College of William & Mary
B.C. Holloway, College of William & Mary
Correspondent: Click to Email
Field emission from carbon nanostructures such as carbon nanotubes (CNT), carbon nanofibers (CNF) and carbon nanosheets (CNS) is greatly influenced by the presence of hydrogen adsorbed on the surface and dissolved in the bulk. The amount and site location of the hydrogen and how it affects electron emission has, to date, not been determined. Temperature desorption spectroscopy, electron energy spectroscopy and time of flight-secondary ion mass spectrometry were employed to examine some of these characteristics. Hydrogen was desorbed from CNS via vacuum firing (T~ 1000@degree@C for 2h for full depletion) and via thermal conditioning at emission currents of greater than 500 uA for periods of 30 min to > 2h. Following conditioning of the CNS, there was a marked improvement in the repeatability, stability and magnitude of the field emission current. Field emission was observed to increase by over an order of magnitude corresponding to the complete removal of hydrogen from CNS. Turn on voltages less than 0.8 V/@micron@ and current densities greater than 2 mA/mm2 have been observed. Raman spectroscopy performed on the CNS after conditioning revealed a significant reduction in the D/G ratio. Comparisons to the reported decrease in electron emission with hydrogen removal from CNT are presented.