Impact of axial strain on drain current of carbon-nanotube field-effect transistors with doped junctions

The effect of axial strain on the performance of carbon-nanotube field-effect transistors with doped junctions is studied. When the diameter of carbon nanotubes (CNTs) is less than 1.5 nm, the decrease of the off-current by axial strain occurs together with the decrease of on-current. However, if the diameter of CNTs is larger than 1.5 nm, axial strain is effective for decreasing off-current while enhancing the on-current at the same time. The decrease of off-current is due to the opening of the bandgap by axial strain, whereas the increase of on-current is attributable to current flowing through the first excited state.