title: Thermionic field emission transport in carbon nanotube transistors.
abstract: With experimental and analytical analysis, we demonstrate a relationship between the metal contact work function and the electrical transport properties saturation current (Isat) and differential conductance (σsd=∂Isd/∂Vsd) in ambient exposed carbon nanotubes (CNT). A single chemical vapor deposition (CVD) grown 6 mm long semiconducting single-walled CNT is electrically contacted with a statistically significant number of Hf, Cr, Ti, Pd, and Au electrodes, respectively. The observed exponentially increasing relationship of Isat and σsd with metal contact work function is explained by a theoretical model derived from thermionic field emission. Statistical analysis and spread of the data suggest that the conduction variability in same CNT devices results from differences in local surface potential of the metal contact. Based on the theoretical model and methodology, an improved CNT-based gas sensing device layout is suggested. A method to experimentally determine gas-induced work function changes in metals is also examined.
authors.affiliation: Department of Electrical Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15219, United States.
authors.forename: David J
authors.initials: DJ
authors.lastname: Perello
authors.forename: Seong Chu
authors.initials: SC
authors.lastname: Lim
authors.forename: Seung Jin
authors.initials: SJ
authors.lastname: Chae
authors.forename: Innam
authors.initials: I
authors.lastname: Lee
authors.forename: Moon J
authors.initials: MJ
authors.lastname: Kim
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Lee
authors.forename: Minhee
authors.initials: M
authors.lastname: Yun
mesh_terms: D017076:Computer-Aided Design; D003460:Crystallization / Q000379:methods*; D004579:Electron Transport; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008422:Materials Testing; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013696:Temperature; D014173:Transistors, Electronic
chemical_list: D037742:Nanotubes, Carbon