SURFACE-STRUCTURE OF HIGH-INDEX AND LOW-INDEX GAAS-SURFACES - DIRECT FORMATION OF QUANTUM-DOT AND QUANTUM-WIRE STRUCTURES

We have observed the formation of well ordered surface structures on the non-singular (331), (311), (211), and (210) GaAs surfaces and on the singular (110) and (111) GaAs surfaces during MBE. RHEED directly reveals the formation of periodically arranged macrosteps with spacings and heights in the nanometer range. Non-singular planes break up into singular surface configurations whereas the singular surfaces transform into vicinal planes. Surface reconstruction plays an important role for the stabilization of the terrace and step widths. The surface structures give rise to lateral quantum size effects which drastically change the electronic properties of GaAs/AlAs multilayer structures.