Effects of surface roughness and alloy disorder on the density of states in semiconductor quantum wires

We calculate the effects of surface roughness and alloy disorder on the density of states (DOS) in cylindrical semiconductor quantum wires with inclusion of a Hubbard local-field correction. It is found that the disorder-induced DOS tail becomes much larger and much more extended below the subband edge when reducing the wire size. Further, the DOS tail at low energies may be enhanced by the Hubbard correction by up to several orders of magnitude. A possibility of applying our results to describe the observed inhomogeneous broadening of exciton lines in the absorption and emission spectra of quantum wires is discussed.