Natural Superstep Formed on GaAs Vicinal Surface by Metalorganic Chemical Vapor Deposition

Abstract

GaAs surfaces and AlAs/GaAs interfaces grown on GaAs vicinal (001) substrates by metalorganic chemical vapor deposition (MOCVD) are observed by transmission electron microscopy (TEM). Under high As pressure, step flow growth is obtained. However, under very low As pressure, supersteps with about 20-monolayer step height are formed during AlAs/GaAs multilayer growth. The mechanisms of superstep formation are discussed. These supersteps can be applied to the new-type quantum well wires with 10 nm dimension without using patterned substrates.