Synthesis of vanadium oxides by pulsed laser deposition and rapid thermal annealing

Abstract

Vanadium dioxide (VO2) is a well-known material for its semiconductor to metallic (SMT) phase change at 68 °C. Temperature controlled changes in optical, structural and electrical properties may lead to many applications in photonics, plasmonics and electronics. The present study explores vanadium oxide thin films growth by Pulsed-Laser Deposition and Rapid Thermal Annealing. 25 nm thick films are synthesized on various substrates, and analyzed by optical spectroscopy, ellipsometry, Raman, SEM and AFM. This work demonstrates the ability to reliably grow vanadium oxide with good phase change properties on amorphous and crystalline substrates, including TiO2 thin films useful for diffraction based optical applications. Thin films with transmittance shift in the order of 40% could be obtained with rapid thermal annealing temperature as low as 350 °C. It is shown that by modifying the annealing temperature, both the transition temperature and hysteresis parameters can be controlled, with however a strong influence of the substrate crystallinity. Transition temperatures as low as 52 °C and hysteresis width as small as 3 °C could be obtained.