OPTICAL SINGULARITIES IN DOPED QUANTUM-WELL WIRES

We present the calculation of emission and absorption spectra of single quantum-well wires doped with electrons. By solving an effective Bethe-Salpeter equation we show the inadequacy of an on-site electron-hole interaction for describing the optical singularities appearing at the band bottom and at the Fermi edge. With the use of a statically screened Coulomb interaction we study the necessity of hole localization in order to get significant singularities. The effect of wire width, carrier density, and temperature is analyzed in the cases of having electrons in one or two subbands. The existing experimental evidence in multiwires is discussed in light of our results.