ELASTIC ENERGY RELAXATION AND CRITICAL THICKNESS FOR PLASTIC DEFORMATION IN CORE-SHELL InGaAs/GaAs NANOPILLARS

摘要

We report on the core-shell InGaAs/GaAs nanopillars grown by metal organic chemical vapor deposition on silicon substrates. The core diameter is about 600 nm, the shell thickness is around 160 nm, the lattice mismatch is 2%. The transmission electron microscopy studies reveal an excellent crystal quality in the entire pillar with no noticeable defects even though the critical thickness for dislocation formation in GaAs shell is only 10 nm in the thin film case. We developed a theoretical model describing a huge increase of the critical thickness owing to the core-shell geometry.