Effective-mass approach for n-type semiconductor nanowire MOSFETs arbitrarily oriented

A method which calculates the effective masses in arbitrarily oriented semiconductor nanowires is presented. In order to avoid the full three-dimensional (3D) resolution of the Schrödinger equation, the method decouples within a Cartesian system the transport direction from the cross section. Results give the new effective mass expressions for each valley and channel orientation. As a direct application, transport in [100]-oriented Ge nanowire metal–oxide–semiconductor field-effect transistors (MOSFETs) is then studied by using a self-consistent 'mode-space' approach expressed in the nonequilibrium Green's function formalism. Along this wire orientation, we show that the effective masses resulting from our approach are very close to the one obtained using a sp 3 tight-binding band-structure calculation for nanowires as thin as 4 nm.