Electric field induced surface diffusion and micro/nano-scale island growth

• Published in: International journal of solids and structures Vol. 45; no. 3; pp. 943 - 958
• Main Authors: Gill, V., Guduru, P.R., Sheldon, B.W.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2008
• Subjects: Electric field; Guided assembly; Island growth; Surface diffusion; Surface instability; Island growth; Electric field; Surface diffusion; Surface instability; Guided assembly
• ISSN: 0020-7683; 1879-2146
• DOI: 10.1016/j.ijsolstr.2007.09.010

An experimental study of electric field induced surface diffusion is presented. A stability analysis of conductive surfaces subjected to a normal uniform electric field shows that sufficiently strong electric fields can destabilize a flat surface, similar to strain induced surface evolution in strain mismatched semiconductor thin films. Further, electric field gradients such as those under a sharp electrode or in the fringe field in a capacitor can drive surface diffusion, leading to nano-scale and micro-scale surface structure growth. Experiments are conducted on gold surfaces at elevated temperatures around 250–350
°C, subjected to electric fields of the order of
10
8
–
10
9
V
/
m
. Growth of islands as ridges was observed, the height of which was as high as 200
nm. A description of the initial surface normal velocity is developed by using the Maxwell–Rowgoski solution for the fringe field at the edge of a parallel plate capacitor.