title: Pathways from disordered to ordered nanostructures from defect guided dewetting of ultrathin bilayers.
abstract: Transitions from spinodal to pattern-guided dewetting of a bilayer of ultrathin films (<10nm) confined between a pair of patterned surfaces have been explored employing molecular dynamic (MD) simulations. The physical or chemical defects of different sizes and shapes are decorated on the confining substrates by either removal or addition of multiple layers of similar or dissimilar atoms. The simulations are performed to identify the transition from spinodal pathway to the heterogeneous nucleation route, with the variation in the size of the substrate patterns. The MD simulations reveal the limits beyond which the defects can guide the dewetting to generate ordered patterns of nanoscopic size and periodicity. Comparing the results obtained from the MD simulations with the more widely employed continuum dynamics approach highlights the importance of the MD approach in quantitatively analyzing the dynamics of the dewetting of ultrathin films. The study demonstrates that the pattern-guided dewetting of confined bilayers can lead to ordered holes, droplets, and stripes with size and periodicity less than 10nm, which are yet to be realized experimentally and can be of significance for a number of future applications.
authors.affiliation: Micro System Technology Laboratory, CSIR - Central Mechanical Engineering Research Institute, Durgapur, India; Academy of Scientific and Innovative Research, Anusandhan Bhawan, New Delhi 110001, India.
authors.forename: Abhiram
authors.initials: A
authors.lastname: Hens
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India.
authors.forename: Kartick
authors.initials: K
authors.lastname: Mondal
authors.affiliation: Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India.
authors.forename: Gautam
authors.initials: G
authors.lastname: Biswas
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India; Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, India. Electronic address: dipban@iitg.ac.in.
authors.forename: Dipankar
authors.initials: D
authors.lastname: Bandyopadhyay
keywords: Instability; Intermolecular interaction; Molecular dynamics; Thin film