Linear theory of unstable growth on rough surfaces
نویسنده
چکیده
Unstable homoepitaxy on rough substrates is treated within a linear continuum theory. The time dependence of the surface width W (t) is governed by three length scales: The characteristic scale l0 of the substrate roughness, the terrace size lD and the Ehrlich-Schwoebel length lES . If lES ≪ lD (weak step edge barriers) and l0 ≪ lm ∼ lD √ lD/lES , then W (t) displays a minimum at a coverage θmin ∼ (lD/lES), where the initial surface width is reduced by a factor l0/lm. The rôle of deposition and diffusion noise is analyzed. The results are applied to recent experiments on the growth of InAs buffer layers [M.F. Gyure et al., Phys. Rev. Lett. 81, 4931 (1998)]. The overall features of the observed roughness evolution are captured by the linear theory, but the detailed time dependence shows distinct deviations which suggest a significant influence of nonlinearities. 68.55.Jk, 81.15.Aa, 68.35.Bs, 81.15.Hi Typeset using REVTEX 1
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