Krishna Kumar1 Mrudula Kavuri1 Parasuraman Swaminathan1

1, Indian Institute of Technology Madras, Chennai, , India

Metallic thin films are unstable in as deposited state. These films tend to break up and agglomerates when annealed. This is known as dewetting and driven by surface energy minimization of the film – substrate interface. Dewetting occurs in both solid and liquid state and while it can be detrimental, where high temperature performance is required, it can also be used to fabricate nanoparticles arrays on substrate for different applications [1].
Enhancing the thermal stability of metallic thin films is of importance, especially for high temperature applications. Recently, we reported that addition of silver nanoparticles on copper thin films suppresses the solid state dewetting of copper thin film [2]. In this work, we explore the effect of added nanoparticles on the liquid state dewetting behaviour of bismuth thin films. We study three system, copper, silver and gold nanoparticles deposited on bismuth thin films on amorphous carbon TEM grids. Transmission electron microscopy results shows that gold and silver nanoparticles accelerate bismuth dewetting, while copper nanoparticles suppress the process. A model is presented to explain these differences.
[1] K. Kumar and P. Swaminathan, “Fabrication of silica nanopillars by templated etching using bimetallic nanoparticles for anti-reflection applications,” Applied Surface Science, under review (2018).
[2] K. Kumar and P. Swaminathan, “Role of silver nanoparticles in the dewetting behavior of copper thin films,” Thin Solid Films, vol. 642, pp. 364–369, 2017.