Impurity-limited mobility of semiconducting thin wire

Abstract

Sakaki [Jpn. J. Appl. Phys. 19, L735 (1980)] has investigated the mobility of semiconducting thin wire structures when the mobility of the wire is limited by scattering from ionized impurities which are located a fixed distance outside the wire. We have used a similar model to theoretically calculate the impurity-limited mobility of such semiconducting thin wires for the cases where the impurities are either in the wire itself (background impurities) or are distributed outside the wire (remote impurities) or are distributed uniformly both inside and outside the wire. For the case of scattering from the background impurities, we find that the mobility decreases with decreasing wire radius d as [ln (kd)]−2 where k is either the thermal or Fermi wave vector of the carriers. For the case of scattering from remote impurities, the size dependence of the impurity-limited mobility depends upon how the remote impurities are distributed outside the wire. When the distribution of ionized impurities outside the wire is uniform, the mobility is independent of the wire radius while, if the ionized impurities are separated from the wire by a fixed distance, we recover the results previously obtained by Sakaki. When the impurities are distributed uniformly both inside and outside the wire, the mobility again is size independent.