EFFECT OF NONPARABOLIC BANDS ON IMPURITY-LIMITED MOBILITY OF SEMICONDUCTING THIN WIRES IN N-TYPE GERMANIUM

The impurity-limited mobility of semiconducting thin wires for nonpara bolic structures in n-type Ge has been investigated by scattering from ionized impurities with doping arsenic. The scattering is coming from the background impurities or from the uniform distribution of remote impurities. Results are shown that the impurity-limited mobility due t o the scattering from background impurities increases slowly and monot onically with increasing temperature for nondegenerate semiconductors at low temperatures. This is the same qualitative property as that for an ordinary three-dimensional semiconducting structure at low tempera tures. However, the mobility due to the scattering from remote impurit ies increases rapidly with temperature and appears much larger than th at from background impurities. It is also shown that the mobility decr eases rapidly and monotonically with the wire radius of semiconducting thin wire for the scattering from background impurities or remote imp urities. For degenerate semiconductors, the impurity-limited mobility decreases monotonically with the wire radius for the scattering from b ackground impurities, but the mobility does not change with the wire r adius quite clearly except a discontinuous point in the neighborhood o f wire radius d < 100 Angstrom for the scattering from remote impuriti es.