PbTe quantum dots multilayer for optical switching device

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.