By using density functional theory in combination with non-equilibrium Green ’s function method to study the effect of central scattering region length on the electron transport properties of N-doped armchair graphene nanoribbons in the center of the right electrode.It is found that the current of armchair graphene nanoribbons with different central scattering region length increases with the increase of voltage under forward bias voltage; while under negative bias voltage

with the increase of central scattering area length

the transmission coefficient in the bias window decreases gradually

the current does not change with the change of voltage

the current value is close to zero

and the device shows obvious rectification characteristics.The result shows that within a certain length range

the rectifying characteristics of the device increases with the increase of scattering length.The reason for this phenomenon may be that there is no transmission peak in the energy range under negative bias voltage.It is important for the design of future graphene rectification devices.