Energetics and electronic structure of tubular Si vacancies filled with carbon nanotubes

Abstract

We studied the energetics and electronic structure of Si nanoscale vacancies incorporating a carbon nanotube (CNT), using first-principles total-energy calculations based on the density functional theory. Our calculations show that the incorporated CNT in the Si nano-tunnel acts as an atom-thickness liner providing the electrostatically flat nanoscale space inside the CNT by shielding the dangling bond states of tubular Si vacancies. The incorporation of CNT into the tubular Si vacancies is exothermic with the energy gain up to 7.4 eV/nm depending on the diameter of the vacancy and encapsulated CNT. The electronic states of the vacancy substantially hybridize with those of the CNT, leading to complex electronic energy band near the Fermi level.

Asymmetric carrier accumulation in double-walled carbon nanotube by an external electric field

“…[14][15][16][17][18][19] Aside from the structural modulation of CNTs, their electronic structures can be tailored by forming hybrid structures with other CNTs and foreign materials. 20,21) In addition to these tailored structures, further variation in their electronic properties is afforded by an external electric field, induced by carrier accumulation in pristine CNTs and in those that are structurally modulated or combined with hybrid structures. In our previous work, defects, structural deformation, and CNT intersections were found to produce unusual distributions of accumulated carriers, inducing a peculiar electric field around imperfections and interfaces induced by external electric fields.…”