Improved heterointerface quality of V-shaped AlGaAs/GaAs quantum wires characterized by atomic force microscopy and micro-photoluminescence

The effects of NH4OH:H2O2:H2O (=1:3:50) etching of the initial V-grooved su bstrate and the use of an AlGaAs/GaAs short-period superlattice buffer laye r on improvement of the interface uniformity of V-shaped AlGaAs/GaAs quantu m wires (QWRs) were investigated by atomic force microscopy and micro-photo luminescence spectroscopy. We found that the surface roughness on the initi al V-grooved substrates induced during V-groove preparation processes could be greatly reduced by the use of the NH4OH etching treatment. Further, by the combined use of the above two techniques, the QWR interface uniformity could be significantly improved, as revealed by both the elongation of the monolayer step islands formed on the (0 0 1) QWR facet and the suppression of step bunching on the (3 1 1)A QWR facet. (C) 2000 Published by Elsevier Science B.V. All rights reserved.