Optical switching of vanadium dioxide thin films deposited by reactive pulsed laser deposition

Abstract

The parameters of reactive pulsed laser deposition were successfully optimized for fabrication of vanadium dioxide thin films. It is observed that the O2 concentration in Ar gas and the total deposition pressure are critical in stabilizing the single VO2 phase. Thermochromic VO2 and V1−xWxO2 (x=0.014) thin films were synthesized on various substrates (silicon, quartz, and sapphire) at 5% of O2/Ar ratio gas and total pressure of 90 mTorr. The structural properties of the deposited films were analyzed by x-ray diffraction, while their semiconductor-to-metal phase transitions were studied by electrical resistivity using the four-point technique and infrared transmittance from room temperature up to 100 °C. The observed transition temperature was about 36 °C for W-doped VO2 compared to 68 °C for VO2 films. This transition temperature was then lowered by about 22.85 °C per 1 at. % of W added. The temperature coefficient of resistance was about 1.78%/°C for VO2 and about 1.90%/°C for W-doped VO2. Using the pump-probe experiment, the application of these thermochromic films as optical switches was demonstrated at the wavelength of 1.55 μm. The transmission switching was about 25 dB for VO2 and 28 dB for W-doped VO2. In addition, application of VO2 on optical fiber components was demonstrated by direct VO2 coating on the end faces of cleaved single mode optical fibers and optical fiber connectors.

Electrically tunable sign of capacitance in planar W-doped vanadium dioxide micro-switches

“…The details of deposition conditions and the switching characteristics of these layers were reported in previous publications [6,7]. Standard photolithography followed by plasma etching was used to pattern the layers into planar micro-switches (100 µm wide by 1000 µm long).…”

The Study of the Effects of Atomic Oxygen Erosion on the Microstructure and Property of Vo2 Thermochromic Coating Using Csa’s Space Simulation Apparatus

“…In this study, two samples of VO 2 coating were deposited on aluminum alloy substrates using laser ablation deposition technic [4]. Metallic vanadium target was used.…”

“…Coating can be deposited on different substrates using various methods including chemical vapor deposition [6], electron beam evaporation [7], RF sputtering [8], sol-gel technique [9], and pulsed laser vacuum deposition [10]. A recent works by Kruzelecky et al [11] and Soltani et al [4] demonstrated that a tuneability of ∼60% in emissivity of VO 2 coating can be achieved by proper control of the stoichiometry and microstructure of the coating. However, there is a concern if space environment, particularly the atomic oxygen, would degrade the performance of the coating.…”

“…VO 2 is a typical thermochromic material, which can change its thermal emittance, also the transmittance and reflectance, due to a metal-insulator phase transition upon the change of environment temperature [4]. Such property can be effectively used to regulate heat rejection by the spacecraft into deep space so as to achieve a passive thermal control for the spacecraft.…”

Synthesis and Physicochemical Properties of Ammonium Tetravanadate for Obtaining Vo2

“…SMPT and electrical switching determine the use of vanadium dioxide in temperature sensors, optical switches, memory elements, energy-saving coatings for glass, optical information carriers, and thermochromic indicators [2][3][4][5].…”