Article révisé par les pairs
| Résumé : | The problem of the advance of a monomolecular step on a low-index face of a growing Kossel crystal is considered in this paper as one of the random-walk type, i.e. the movement of the particles results from discontinuous jumps on the surface and along the edge of the step.If the supersaturation and the jump probabilities, which depend strongly on the temperature, are given, an expression for the lateral growth velocity of the step can be calculated. The result can be brought into the form ν = ν∞Ao, where ν∞ is the velocity of a total absorbing step, while Ao is a factor, which is only a function of the jump probabilities and the mean distance between kinkplaces, and not of the super saturation, and which has a value between 0 and 1.A stationary regime is supposed to be created by taking away the particles, which arrive at the kinkplaces and by bringing these again into the vapour phase. The equations, which state that at every site on the surface or at the edge of the step, the number of arriving particles equals that of the leaving ones, are the basic ones. These enable the calculation of the rate of advance ν of the step.In certain cases the formula for ν can be approximated and the results can be compared with those obtained by Burton, Cabrera and Frank, who have treated the same problem as a continuous diffusion problem. |
