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 nitrogen precursor. The lattice mismatch between InN and GaN is very large and a Stranski-Krastanov (SK) growth mode transition can occur above a critical In composition. However, changing the growth conditions, namely increasing 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) present 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) 2001 Elsevier Science B.V. All rights reserved.