IP: 193.56.67.168 On: Tue, 14 May 2019 19:33:35 Copyright: American Scientific Publishers Delivered by Ingenta COMMUNICATION Copyright © 2005 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Nanoscience and Nanotechnology Vol. 5, 1919–1924, 2005 Preparation and Optical Properties of Au/Teflon Nanocomposites A. V. Goncharenko, 1 2 ∗ D. O. Grynko, 2 K. P. Grytsenko, 2 and V. Z. Lozovski 2 1 Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 106, Republic of China 2 Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 03028 Kyiv, Ukraine Using thermal deposition technique, we have prepared Au/Teflon thin films on glass substrates. To control the film microstructure, both TEM and AFM characterization have been carried out. The visi- ble optical transmission spectra have been measured in-situ. The peak positions and linewidths in the spectra have been identified in terms of the gold nanoparticle shape, size, and arrangement. The results obtained provide evidence for formation of both sphere-like and cylinder-like gold nanoparti- cles in the films. The fraction of each kind of the particles depends on whether the plasma treatment has been used. The treatment is shown to enhance the fraction of the cylinder-like particles. Keywords: Gold Particle Nanocomposites, Teflon Matrix, Surface Plasmons, Plasma Treatment, Optical Transmission. In our drive towards nanotechnology, there is continuous interest in understanding various mechanisms controlling the needed physical properties of nanomaterials. For the materials to be utilized in various devices, it is of par- ticular importance to ensure a film growth process and to manipulate the size and the shape of dispersed parti- cles to obtain desired properties of the materials. At the same time, because of the lack of ability to control accu- rately the size, shape, and interparticle spatial properties, the relationship between microgeometry and the physical properties is frequently poorly understood. It is of value that while technology parameters can vary in wide limits, the physical properties are not usually profoundly altered being often described by some simple models. This fact enables one to consider only a limited number of typical classes of the materials if, of course, their composition is signified. Here we deal with gold/Teflon nanocomposites pertain- ing to a broad spectrum of metal/insulator nanomaterials. Our readers can be aware of the numerous and varied applications of gold composites. One only has to look at an updated quarterly comprehensive list of literature and patents, which can be found in the searchable Techni- cal Database at the World Gold Council website. 1 As the ∗ Author to whom correspondence should be addressed. primary focus of our investigations is on the optical pro- perties, first of all we note that these composites are of interest from the nonlinear optics point of view. Indeed, composite materials consisting of metallic nanoparticles embedded in a dielectric matrix are considered to be engaging optical nonlinear materials due to the potentially high value of their nonlinear optical susceptibility. When the dielectric constant of gold is completely different from that of the surrounding matrix, the macroscopic nonlin- ear susceptibility may be resonantly enhanced near the surface plasmon resonance frequency of the particles. 2–7 Further, the composites are also of interest for sensor applications. Gold is being considered as a very promis- ing metal for sensors because of its chemical stability and unique optical properties. Plus, it is biocompatible— cells do not die on contact with it. On the other hand, Teflon is a very stable insulator, chemically inert and abso- lutely insoluble. One of ways to use the metal/polymer composites as chemical sensors lies in using the swelling phenomenon. At the same time, this phenomenon can be revealed optically. 8–11 Finally, it has been shown that suf- ficiently small gold nanoclusters can exhibit rather strong visible photoluminescence. 12–14 This fact is also of interest from the practical standpoint. The main objective of this communication is to find a correlation between methods of preparation of the J. Nanosci. Nanotech. 2005, Vol. 5, No. 11 1533-4880/2005/5/1919/006 doi:10.1166/jnn.2005.444 1919