Stranski?Krastanov transition and self-organized structures in low-strained AlInN/GaN multilayer structures
Low-strained AlInN/GaN multilayers aimed as Bragg mirrors were grown by metal organic vapour phase epitaxy on GaN/Si(1?1?1). In such structures the upper AlInN/GaN interfaces show a considerable roughening on a nanometre scale whereas the lower ones appear flat as evaluated by cross-sectional electron and transmission electron microscopy. The roughening is attributed to a Stranski?Krastanov transition from two-dimensional layer-by-layer to three-dimensional island growth. In addition, a self-organized wavy-like surface morphology on a micrometre scale is observed in such structures which we discuss in terms of Grinfeld instability.