The effect of vacancy’s percent on the energy gap of zigzag single-walled carbon nanotube

The role of disorder in a single-walled carbon nanotube (SWCNT) is of importance from two perspective; first, in growth process of a SWCNT since some impurity and vacancies are created, second, its application in spintronic devices [1] and also nanomagnets. Also it is shown that the vacancy could lead to electron spin polarization, hence a magnetic SWCNT [2, 3].we investigate how the influence of the vacancy’s percent changes the electronic properties of SWCNT. Especially, the vacancy’s effect on the energy gap is considered by using Green’s function method that is coupled with coherent potential approximation. Our probes in conjunction with computer simulation shows that by increasing this kind of disorder in SWCNT increases the energy gap so, we can convert a metallic SWCNT to semiconductor one or, change a semiconductor SWCNT with low energy gap to a higher energy gap one. Also we predict that by controlling vacancy’s percent, for example, we can change electronic properties of (12, 0) zigzag SWCNT with very small band gap into the electronic properties of (13, 0) SWNT with very larger band gap than (12, 0) SWNT