Between One and Two Dimensions : Quantum Wires Arrays Grown on Vicinal Surfaces

Abstract

After the theoretical prediction of the potential interest of semiconductor low dimensional structures for electronic [1] and optical [2] devices, there has been a tremendous experimental activity to build such nanostructures where the motion of carriers is quantized in more than two dimensions. As the size and the dimensionality shrink, surfaces and interfaces become increasingly important with respect to the core of the nanostructure. It has been proposed several years ago to synthesize quantum wires [3] or quantum dots [4] directly by epitaxy to benefit from the high quality of materials and interfaces provided by epitaxial techniques. Recently, the attractive novel electronic properties of such low dimensional structures have been evidenced. Optical studies have revealed anisotropic properties of serpentine quantum wire arrays [5] and of Lateral Superlattices (LSL) grown on vicinal surfaces [6] in the AlGaAs system, the discrete linewidth of zero-dimensional excitons confined in InAs islands formed on a GaAs substrate after the growth mode switches from a Frank-Van der Merve type to a Stransky-Krastanov one due to the lattice mismatch between InAs and GaAs [7]. Transport studies reveal a strong conductivity anisotropy in LSL grown on vicinal surfaces [8] whereas Coulomb blockade has been observed in the magneto-capacitance study of InAs dots formed on GaAs [9].