Effects of carbon matrix pressure on xenon atoms

Author(s)

Myriano Henriques de Oliveira Junior

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin
• Defense date: 2005-11-03

Examining board members

Francisco das Chagas Marques; Gustavo de Medeiros Azevedo; Iris Concepcion Linares de Torriani

• Advisor: Francisco das Chagas Marques

Abstract

In this work it was prepared a series of amorphous carbon thin films using the ion beam assisted deposition technique. We used a xenon ion beam in order to sputter a graphite target with a fixed energy of 1500eV for all samples set up. A second ion beam was used as an ion assisting beam during the deposition with different energy for each film but, always in the range of 0 to 400eV. As the bombardment energy is varied the film produced can have a structure more or less compact which implies in a pressure rising along the amorphous net, called intrinsic stress. Another consequence of the bombardment is the xenon incorporation. By RBS measurements it was observed a concentration of about 3 to 4% of this noble gas inside the films, which belong to the same range where is observed a condensation of this element in solid clusters when implanted in crystalline metals or semiconductors. From XAS measurements, with radiation energy within a range involving the Xe L3 absorption edge, those solid clusters formation were observed. With some computational simulations compared to those experimental results we were able to have a better comprehension about XANES fine structure. We used SAXS measurements to try to determine some geometrical parameters beyond those obtained by XAS. As the xenon clusters dimensions are too small (probably of about ten atoms) it is difficult to detect them by this technique with the experimental parameters used but, it was observed some structures that seem to be shaped and have characteristics dimensions varying from 10 to 25nm. What seem to be graphitic planes clusters, once amorphous carbon thin films prepared by IBAD are graphitic-like (AU)