Width distribution of nanowires grown by step decoration

The homogeneity of Cu nanowires on a stepped Mo(110) surface is determined from scanning tunneling microscopy images via semi-automatic pattern recognition. The width distribution along a wire is close to a Poisson distribution when measured in units of atomic rows N. The standard deviation sigma follows the relation sigma approximate to 1.3 root[N]. The average wire width [N] is proportional to the terrace width for growth at similar to 500 degrees C, and independent of the terrace width when growing at similar to 600 degrees C and higher, where Cu atoms diffuse across step edges. Possible driving forces for the equilibration of the wire width are discussed, such as edge strain minimization, electrostatic step-step interactions and electronic quantum size effects. (C) 1998 Elsevier Science B.V. All rights reserved.