Mechanisms of self-ordering of nanostructures in nonplanar OMCVD growth

Despite the wide use of OMCVD on V-grooves in semiconductor quantum wire fabrication, the details of the physics of self-limiting growth at the bottom of such grooves have not been addressed so far. We have developed an analytic model that explains quantitatively this self-limiting growth. Gradients of chemical potential, due to the non-planarity of the surface. induce capillarity fluxes towards the bottom of the grooves. The self-limiting profiles result from an interplay between the effects of growth rate anisotropy on the different planes composing the groove (that tend to sharpen it) and of capillarity (that tend to broaden it). During ternary growth, effects of the entropy of mixing add to the curvature-related ones, modifying the self-limiting shape. Monte Carlo simulations confirm this diffusion model, evidencing the importance of orientation-dependent incorporation rates. Comparison with experimental results are presented and discussed.