EFFECTS OF A KINETIC BARRIER ON LIMITED-MOBILITY INTERFACE GROWTH MODELS
Rótulo films, kinetic, barrier, Ehrlich-Schwoebel, (ES), step, barriers, Wolf-Villain, Das, and, Sarma-Tamborenea, models
ResumoA rich variety of morphologies can be observed during far-from equilibrium growth processes and many of them with potential for technological application. Growth instability can induce three-dimensional mound-like patterns in different types of films such as metals, inorganic and organic semiconductors materials to cite only a few examples. Such a growth instability has been mainly attributed to the presence of Ehrlich-Schwoebel (ES) step barriers that reduce the rate with which atoms move downwardly on the edges of terrace leading to net uphill flows. Growth instabilities can also emerge from topologically induced uphill currents which depend on the crystalline structure or from fast diffusion on terrace edges among other mechanisms. The existence of ES barriers is supported by molecular dynamic simulations. The role played by a kinetic barrier originated by out-of-plane step edge diffusion, introduced in Leal et al, J. Phys. Condens. Matter 23, 292201 (2011), is investigated in the Wolf-Villain and Das Sarma-Tamborenea models with short range diffusion. Using large-scale simulations, we observed that this barrier is suffcient to produce growth instability, forming quasiregular mounds in one and two dimensions. The characteristic surface length saturates quickly indicating a uncorrelated growth of the 3d structures, which is also confirmed by a growth exponent $\beta = 1/2$. The out-of-plane particle current provides a large reduction of the downward flux enhancing, consequently, the net upward diffusion and formation of 3d self-arranged structures.
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PEREIRA, A. EFFECTS OF A KINETIC BARRIER ON LIMITED-MOBILITY INTERFACE GROWTH MODELS. Anais do Salão Internacional de Ensino, Pesquisa e Extensão, v. 11, n. 2, 28 ago. 2020.