Ag fractals formed on top of a porous TiO2 thin film. Issue 7 (7th June 2016)

• Record Type: Journal Article
• Authors: Borges, J.; Rodrigues, M. S.; Lopes, C.; Costa, D.; Ferreira, A.; Pereira, R. M. S.; Costa, M. F.; Vasilevskiy, M. I.; Vaz, F.
• Is Part Of: Physica status solidi. Volume 10:Issue 7(2016)
• Page Start: 530
• Page End: 534
• Publication Date: 2016-06-07
• Subjects: silver -- fractals -- TiO2 -- surface plasmon resonance -- diffusion‐limited aggregation; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201600131
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : This work demonstrates the formation of Ag fractals on top of a Ag:TiO2 thin film. The dendrite‐type objects emerged from a homogeneous and highly transparent Ag:TiO2 nanocomposite, via the mechanism of diffusion‐limited‐aggregation of Ag atoms, during heat‐treatment at 500 °C. A porous TiO2 matrix was also formed during this process, opening a wide range of possible applications, namely in sensing‐based ones, together with surface enhanced spectroscopies. Furthermore, fractals incorporate a wide range of shapes and spatial scales, inducing a potentially interesting optical response, over the whole visible range, presumably related with localized surface plasmon modes with very broad spectral distribution. Ag fractals on porous TiO2 matrix, emerged from a sputtered Ag:TiO2 nanocomposite thin film, after annealing at 500 °C. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) Abstract : Ag:TiO2 nanocomposite thin films were prepared by magnetron sputtering and the mechanism associated to the formation of dendrite‐type fractals was found to be controlled by diffusion‐limited‐aggregation of Ag atoms, promoted by a thermal annealing. The fractal structures that were formed became surrounded by a porous TiO2 matrix, and are expected to find important applications in surface enhanced spectroscopies and plasmonic sensing.