Electrical Characteristics of a Carbon Nanotube-Functionalized Probe for Kelvin Probe Force Microscopy

Abstract

Carbon nanotubes (CNTs) have been demonstrated as a functional probe for scanning probe microscopy because of their good mechanical properties, small diameter, and high aspect ratio. However, their application and performance in Kelvin probe force microscopy (KPFM) are largely unexplored. Here, the electrical properties of CNTs used as the KPFM probe in terms of surface potential measurement and mapping are investigated. The local contact potential difference measured by the CNT probe on the Ag( 111) surface shows a dependence on tip− sample distance, indicative of the existence of a permanent dipole moment at the end of CNT tips. A model is established to quantify the dipole moment of the CNT using in situ measured geometric parameters, thereby deriving the precise work function difference between the CNT tip and the metal substrate. The enhanced spatial resolution in surface potential mapping using the CNT-functionalized probe as compared to conventional metal probes is attributed to the small radius of the CNT tip and the presence of a spontaneous dipole moment at the tip apex.

Interlayer Conductance in the Armchair Nanotube - Zigzag Graphene Ribbon Parallel Contact: Theoretical Proposal of Detection of Wavefunction Growing from the Edge to the Center in the Graphene Ribbon

“…The thermal vibration and shift from the AB stacking break the relation H (l.l+1) = H (l,l−1) and weaken the (−1) l−l ′ cancelation in Eq. (7). These issues should be addressed in future studies.…”

“…However, the phase of the ZGR wave function strongly suppresses the contribution of oblique bonds, allowing the selective detection of the growing component.Since their discovery, 1) carbon nanotubes (NT) have attracted significant attention owing to their electronic and mechanical properties, accompanied by high aspect ratios. 2, 3) These characteristics are suitable as tips of atomic force microscopy, [4][5][6] Kelvin force microscopy, 7,8) electrical probes, 9,10) and scanning tunneling microscopy (STM); [11][12][13] the nanometer-sized radius guarantees a high spatial resolution. Using the chiral index (n 1 , n 2 ), the NTs were metallic when n 1 − n 2 was a multiple of three (mod(n 1 − n 2 , 3)=0) and semiconducting otherwise (mod(n 1 − n 2 , 3)=1,2).…”