Metal-Nanotube Contact
We present first principle calculation of the Schottky barrier and tunneling barrier height at the metal (Au, Pd, Pt) semiconducting (8,0)nanotube interface. It is found that Schottky barrier height depends on the detailed atomic geometries at the interface. Two most important factors are the metal species and its crystal orientation. They have considerable influence on the reactivity of the surface and effectiveness of dipole formation, which leads to variations in Schottky barrier height. Pd is found to have the lowest Schottky barrier. Our ab initio results are in good agreement with experimental observations.
Figure 1. Total energy of metal/CNT as a function of a) interfacial distance. b) rotational angle c) translation along tube axis. The reference energy is taken as metal/CNT separated by infinite distance. Pt(100) curve in (a) is shifted up 0.2eV for clarity.
Figure 2. Schottky Barrier height and tunneling barrier height for different metal/(8,0)CNT combinations as a function of interfacial distance. Solid squares indicate Schottky Barrier Height(right axis) and empty dots indicates Tunneling Barrier Height(left axis). Dashed line indicates equilibrium distance (a)Au(111)/CNT (b)Au(100)/CNT (c) Pd(111)/CNT (d)Pd(100)/CNT (e)Pt(111)/CNT (f)Pt(100)/CNT
Nugget for NCN Annual Report provided by K. J. Cho of Stanford.