Current transport in semiconductor nanowires with built-in barriers based on a 1D transfer matrix calculation

Abstract

A one dimensional (1D) transfer matrix calculation of current transport in semiconductor nanowires with built-in barriers is described within the effective mass approximation by taking into account (i) the quantum confinement in the radial direction and (ii) the Fermi level position with respect to the 1D sub-band(s), both of which can be determined analytically. We calculate the current-voltage (I-V) characteristic for an InAs nanowire, which has a radius of 200 Å and two 50 Å InP, built-in barriers, which define a 150 Å long InAs quantum disk and find that a peak in the current occurs at an applied voltage of 72 mV, corresponding to resonant tunneling of carriers through the double barriers. This is in good agreement with the I-V curve measured in a similar nanowire at a temperature of 4.2 K, where resonant tunneling occurs at 80 mV. It is deduced that the Fermi level is ≈26 meV above the conduction band edge at the surface of the specific InAs nanowire, which is ten times lower than the Fermi level pinning at inverted InAs thin film surfaces. We discuss the importance of the strain and surface depletion.