Humidity sensors applicative characteristics of granularized and porous Bi2O3 thin films prepared by oxygen plasma-assisted pulsed laser deposition

• Humidity sensors applicative microstructures in Bi2O3 thin films.
• The effects of substrate temperature on to Bi2O3 granulation and porosity.
• Conductivity–frequency characteristics of O2 plasma-assisted PLD Bi2O3 thin films.
• Humidity sensors sensitivity, response and recovery times of Bi2O3 thin films.

Pulsed laser ablation of pure bismuth targets in a plasma discharge followed by thermal treatment as preparation method for humidity high-sensitive bismuth trioxide thin films deposited onto Si/Pt substrates were analyzed. Several thin films were deposited at different substrate temperatures during the pulsed laser deposition namely between 300 °C and 600 °C. Near to the electrical investigation, the structure and the morphology of the films as keys features for water adsorption are thoroughly investigated and correlated with their sensitivity as humidity sensors. Thus, it has been found that strong granularized Bi2O3 thin films obtained through oxygen plasma-assisted pulsed laser deposition onto Si/Pt substrate at 500 °C provide the most interesting humidity sensing characteristics.