| AVS 58th Annual International Symposium and Exhibition | |
| Nanometer-scale Science and Technology Division | Monday Sessions |
| Session NS+EM-MoM |
| Session: | Nanowires and Nanoparticles I: Assembly and Devices |
| Presenter: | Raphael Clearfield, North Carolina State University |
| Authors: | R. Clearfield, North Carolina State University J.D. Fowlkes, Oak Ridge National Laboratory P.D. Rack, University of Tennessee Knoxville N. Samatova, Oak Ridge National Laboratory A.V. Melechko, North Carolina State University |
| Correspondent: | Click to Email |
Heat applied to thin films below a critical thickness will generally cause transformation of the film into isolated particles. This process is known as dewetting. Solid state dewetting occurs below the melting temperature of the film and is governed by diffusive mass transport. Currently two mechanisms of dewetting are distinguished: hole nucleation and growth, and spinodal dewetting. Spinodal dewetting proceeds via film surface undulations that have characteristic wavelengths related to the thickness of the film. Lithographic patterning of thin films has been utilized to direct the dewetting instability development toward designed nanostructured geometry of nanoparticle arrays. Tailoring the geometry of thin film edge have been shown to affect both heterogeneous nucleation and spinodal dewetting regimes. Nanoimprint lithography, conventionally used for definition of the edges of thin films, is a fabrication method where a stamp is pressed into a thin normally monomer or polymer film at elevated temperatures. Nanoimprinting can also be conducted in direct mode where the stamp is pressed into a metallic film. Surface undulations characteristic for spinodal dewetting will be used to direct the stamp design. Such imprinting allows setting initial conditions, programming instability, in the thin metallic film that is linked to the spinodal surface instability. In this work we are presenting the results of the investigation into behavior of thin films in which a 3D structure has been imprinted. We present observations on the effect of direct nanoimprint lithography on nanoscale Au and Ni films using periodic arrays of cylinders. Our focus is on the spatial distribution of the particles produced from dewetting of the nanoimprinted films. Particles in patterned regions are characterized in terms of their spacing, periodicity and size, and shape. The geometry of the dewetted patterns is compared to that of the 3D features created after direct nanoimprinting of the films. Analysis of spatial correlation of the final dewetted patterns to stamp patterns is presented.