Roles of alkali-metal adsorption and defect position on work functions of capped single-wall carbon nanotubes

摘要

The influence of alkali-metal adsorption positions and defects positions on work functions of (5, 5) single-walled carbon nanotubes (CNTs) with a capped edge had been investigated by first-principles calculations. An single-walled armchair (5, 5) CNT with a capped edge was assumed. A single vacancy defect was created by removing a carbon atom from different atomic layers (which were labeled as T1–T4 in FIG. 1(a)). The alkali-metal adatoms (Li/Na/Cs) were located above the center of the pentagons or hexagons (which were labeled as P1–P4 in Fig. 1(b)) on the caps for the perfect CNT (P-CNT), while they were associated with defective CNTs (D-CNTs) on the vacancy defects.