Mechanisms of self-ordering of nanostructures in nonplanar OMCVD growth

Despite the wide use of OMCVD on V-grooves in semiconductor quantum wire fa brication, 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 analy tic model that explains quantitatively this self-limiting growth. Gradients of chemical potential, due to the non-planarity of the surface. induce cap illarity fluxes towards the bottom of the grooves. The self-limiting profil es result from an interplay between the effects of growth rate anisotropy o n the different planes composing the groove (that tend to sharpen it) and o f 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, evid encing the importance of orientation-dependent incorporation rates. Compari son with experimental results are presented and discussed. (C) 1998 Elsevie r Science B.V. All rights reserved.