PbTe quantum dots multilayer for optical switching device

摘要

In this work we report the fabrication of PbTe quantum dots multilayers embedded in SiO2 by alternatively use of Laser Ablation and Plasma Enhanced Chemical Vapor Deposition techniques. The quantum dots were grown by pulsed laser deposition (PLD) of a PbTe target using the second harmonic of a Q-Switched Quantel Nd:YAG laser in high purity argon atmosphere. The glass matrix was fabricated by PECVD using tetramethoxysilane (TMOS) as precursor. The RF power was supplied by a RF-150 TOKYO HI-Power operating at 13.56 MHz and coupled to the RF electrodes through a matching box. The deposition rates as well as the best growth parameters for both the nanoparticles and the glass matrix were obtained from a previous work. The morphological properties of the nanostructured material were studied by means of igh Resolution Transmission Electron Microscopy(HRTEM), grazing-incidence small-angle X-ray scattering (GISAXS) and X-ray reflectometry . Unlike HRTEM, which extracts information of a submicron region of the sample and only a few thousand particles are observed, GISAXS signal is obtained through an average over orders of magnitude larger number of particles (perhaps 1012 particles) distributed over an area of tens of square millimeters. This fact means that GISAXS sampling is much more representative of the sample as whole. Finally, multilayers were grown inside a Fabry-Perot cavity. The complete system operates as an optical switching device for the infrared region. The device was characterized by Scanning Electron Microscopy and optical absorption.