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

摘要

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 NH_3 flux, allows one to promote the 2D growth. This phenomenon can be ascribed to a surfactant effect of hydrogen atoms (or NH_x 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.