Importance of boundary conditions to conduction in short samples

The effects of boundary conditions on conduction in short samples are calculated numerically for nonballistic and ballistic cases. For the nonballistic case, the resistivity is substantially below the bulk value due to spillover from N
⁺
contacts even for samples which are several Debye lengths long. In the ballistic case, it is found that changing the boundary conditions strongly affects both the magnitude of the current and its dependence on voltage.