Ellipsoidal band structure effects on current-voltage characteristics in silicon nanowire transistors

We have investigated the validity and limitation of isotropic effective-mass approximations to electronic states in circular-shaped silicon nanowire transistors by comparing current-voltage characteristics. We find that for smaller diameters, the harmonic mean approximation gives the best agreement with the exact elliptic result, while for larger diameters, the geometric mean approximation approaches the exact result.