Humidity sensors applicative characteristics of granularized and porous Bi 2 O 3 thin films prepared by oxygen plasma-assisted pulsed laser deposition

Bismuth Oxide Thin Films for Optoelectronic and Humidity Sensing Applications

“…at 3 Á 10 À5 Torr). Given the great variability of the types of bismuth oxides that can form and of their properties, depending on the mode and conditions of preparation, it can be chosen to obtain bismuth oxide thin films by the PLD technique by varying: the nature and temperature of the substrate during the depositions, or/and the wavelength (193 or 266 nm) and number of laser pulses (40,000 or 60,000) used for ablation [28][29][30]. Pure bismuth targets (e.g.…”

“…An RF source with 13.45 MHz and 150 W can be used for the radio frequency (RF) discharge of the oxygen inside the deposition chamber. Various materials can be employed as substrates at PLD, from microscope glass slides to silicon, Si (100) or/and Si/Pt, respectively, but the latter proved to give rise to spectacularly different properties of the bismuth oxide films, with electrical resistance up to three orders of magnitude lower than the films deposited on glass and also with a very high sensitivity to humidity as compared to the other prepared films [28]. Substrate heating during the PLD process can also be tried, since this parameter is crucial for the structure, the morphology and the other properties of the deposited films, by controlling the movement, combination, and accumulation of deposing atoms on the substrate.…”

“…The deposition of bismuth trioxide can be accomplished by virtually any known method used for thin films: thermal evaporation [11,[20][21][22][23][24]; pulsed laser ablation-PLD [25][26][27][28][29][30], spray pyrolysis [31][32][33], electrodeposition [34], sol-gel [35], etc. Depending on the chosen deposition method, on its conditions (nature and temperature of the substrate, the vacuum level, the nature and pressure of the ambient gases, etc.)…”

“…The preparation of bismuth oxide thin films by the PLD (pulsed laser deposition) technique has been rarely used [25][26][27][28][29][30] because of its relative novelty and of the high cost of the necessary equipment (deposition unit, powerful laser devices, high vacuum, etc. ).…”

Microstructure, electrical and humidity sensing properties of light rare earths zirconates

“…The reliability tests did not show significant differences between light rare earths zirconates sensors. Comparatively with other materials [44][45][46], humidity sensors based on light rare earths zirconates show high sensitivity, medium response and recovery times, but have in compensation the advantage of high physical and chemical stability.…”