On the sensing properties of Nb2O5 films prepared by pulsed laser deposition

This paper reports the electrical characterization of the sensing properties of nanostructured Nb2O5 films deposited by Pulsed Laser Deposition (PLD) towards ethanol gas. In particular, a sensing thin film was deposited by 2000 pulses of Nd:YAG UV laser (operating at λ = 266 nm and energy of 112 mJ) obtaining a porous layer composed by vertical nano-pillars with a thickness of about 500 nm. The sensing film was characterized in a temperature operating range from 340 °C to 450 °C, identifying the optimal working temperature at 420 °C. Sensing response toward ethanol was determined in a concentration range from 50 ppm to 100 ppm. Response repeatability, stability, reversibility and recovery times were tested as well. The preliminary characterization highlighted the very promising sensing performance of PLD niobium oxide thin films. Therefore, the investigation of ethanol gas sensors based on PLD sensing layers grown in different conditions to tune nanostructure and thickness, is in progress in order to further increase the sensor sensitivity and selectivity.