SURFACE-STRUCTURE VARIATION CAUSED BY ANNEALING

The variation of surface microstructure caused by annealing for a Pt s ingle crystal is studied by means of reflection electron microscopy (R EM). The monatomic steps are characterized by fractal dimensions. The fractal dimension of a monatomic step increases during annealing. The increasing fractal dimension during annealing indicates that new kinks appear at the straight section of the atomic step. The higher the fra ctal dimension of a step, the faster the step migration. This phenomen on is expained using the activation energy of evaporation. Although th e step migration and expansion of atomic depressions caused by anneali ng are often observed, atomic islands formed by atom deposition have n ot been observed in our experiments. (C) 1998 Elsevier Science B.V. Al l rights reserved.