The impact of vacancy defects on the performance of a single-electron transistor with a carbon nanotube island

The single-electron transistor (SET) principle of operation is based on the Coulomb blockade (CB) phenomenon. The island material and associated defects have a direct impact on the range of the CB effect and the operating speed of the SET. In this research, the impact of vacancy defects on a SET-based on a carbon nanotube (CNT) is investigated. The results show that a SET with six atomic vacancies exhibits the lowest Coulomb diamond area and highest operating speed. The results also show that increasing the distance between two single vacancies decreases the Coulomb diamond area of the SET. Moreover, the location of the vacancies in the CNT and its effect on the operation of the SET are investigated. The comparison study shows that an antidote vacancy in the CNT close to the drain side results in the shortest CB range and narrowest bandgap, resulting in the CNT SET with the highest operating speed.