TEM study of GaN/AlN quantum dots deposited on vicinal silicon

Transmission electron microscopy was performed to investigate the use of AlN epitaxial films deposited on vicinal Si(111) as templates for the growth of GaN quantum dots. It is found that the substrate vicinality induces both a slight tilt of the AlN (0001) direction with respect to the (111) direction and a step bunching mechanism. As a consequence, a dislocation dragging behavior is observed giving rise to dislocation-free areas well suited for the nucleation of GaN quantum dots. The microstructure of different QD encountered in the GaN/AlN system is also described.Transmission electron microscopy was performed to investigate the use of AlN epitaxial films deposited on vicinal Si(111) as templates for the growth of GaN quantum dots. It is found that the substrate vicinality induces both a slight tilt of the AlN (0001) direction with respect to the (111) direction and a step bunching mechanism. As a consequence, a dislocation dragging behavior is observed giving rise to dislocation-free areas well suited for the nucleation of GaN quantum dots. The microstructure of different QD encountered in the GaN/AlN system is also described