Self-organizing nanochannel networks in periodically perforated semiconductor films

Abstract

In this paper we theoretically analyze the mechanism of nanochannel formation by an evolutionary etching process in periodically perforated semiconductor films. The compressive stresses due to lattice mismatch of the epitaxially grown nanoscale films are gradually relaxed; leading to an evolutionary buckling process. We quantitatively analyze the mechanics of wrinkle evolution around an isolated etch-pit, and a predictive tool to determine the edge-to-corner channel transition is developed. The buckling wavelength increases with increasing etch depth until the etch fronts of neighboring etch-pits merge and multiple channels coalesce. The effect of various system parameters such as etch-pit size, periodicity, and film thickness on the channel morphology has been studied and compared with experimental results. The good agreement provides insight into the physical mechanisms that govern the complex interplay during evolutionary etching and channel formation.