Polarization anisotropy in quasiplanar sidewall quantum wires on patterned GaAs (311)A substrates

The polarization anisotropy of the photoluminescence from quasiplanar quantum wires fabricated on the sidewall of [0(1) over bar 1]-oriented mesas on the (311)A GaAs surface is investigated using a modulation technique that combines high spatial (similar to 1 mu m) and polarization resolution (< 0.1%). Due to their low symmetry, (311)A-oriented quantum wells are intrinsically anisotropic with the fundamental transition preferentially oriented along the [(2) over bar 33] direction. The anisotropy contribution from the lateral confinement in the [0(1) over bar 1] wires opposes that from the vertical confinement. With increasing lateral confinement, the wire anisotropy initially reduces and then changes its sign. The lateral extent of the electronic wave functions involved in the anisotropic transitions is obtained from a comparison of the results with a theoretical model. (C) 1999 American Institute of Physics. [S0021-8979(99)07012-7].