InGaN heterostructures grown by molecular beam epitaxy: from growth mechanism to optical properties

GaN and InGaN layers are grown by molecular beam epitaxy using ammonia as n itrogen precursor. The lattice mismatch between InN and GaN is very large a nd a Stranski-Krastanov (SK) growth mode transition can occur above a criti cal In composition. However, changing the growth conditions, namely increas ing the NH3 flux, allows one to promote the 2D growth. This phenomenon can be ascribed to a surfactant effect of hydrogen atoms (or NHx radicals) pres ent at the growth surface. The optical properties of InGaN/GaN quantum dots , made by SK growth mode, and InGaN/GaN quantum wells are compared. (C) 200 1 Elsevier Science B.V. All rights reserved.