title: Gas ionization sensors with carbon nanotube/nickel field emitters.
abstract: Gas ionization sensors based on the field emission properties of the carbon nanotube/nickel (CNT/Ni) field emitters were first developed in this work. It is found that the breakdown electric field (E(b)) slightly decreases from 2.2 V/microm to 1.9 V/microm as the pressure of H2 gas increases from 0.5 Torr to 100 Torr. On the contrary, E(b) obviously increases from 2.9 V/microm to 6.5 V/microm as O2 gas pressure increases from 0.5 Torr to 100 Torr. This may be explained by the depression of the electron emission that caused by the adsorption of the O2 gas on the CNT emitters. The Raman spectra of the CNT/Ni emitters also show that more defects were generated on the CNTs after O2 gas sensing. The Joule heating effect under high current density as performing H2 sensing was also observed. These effects may contribute the pressure dependence on the breakdown electric field of the CNT/Ni gas ionization sensors.
authors.affiliation: Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan, ROC.
authors.forename: Bohr-Ran
authors.initials: BR
authors.lastname: Huang
authors.forename: Tzu-Ching
authors.initials: TC
authors.lastname: Lin
authors.forename: Ying-Kan
authors.initials: YK
authors.lastname: Yang
authors.forename: Shien-Der
authors.initials: SD
authors.lastname: Tzeng