Room-temperature polymer-coated supersonic cluster beam deposited ZnO film for O₂ gas and dissolved O₂ sensing

Abstract

Room-temperature dynamic light-enhanced galvanometric response of supersonic cluster beam deposited (SCBD) zinc oxide (ZnO) films to oxygen (O2) was investigated. The photocurrent was recorded when above-bandgap light is turned on, being maintained and turned off. Measurements were done in dry gaseous environment, and repeated in dry and wet gaseous environment after adding a water-proof superhydrophobic polymer coating on top. A dissolved oxygen sensor prototype made of a polymer-coated ZnO film was fabricated to detect oxygen content in water. A model involving photo generation and recombination of electron-hole pairs, trapping and release of conduction electrons associated with sorption-desorption processes of oxygen was proposed. A practical method for determining the O2 concentration in the media based on fitting parameters to the dynamic photocurrent was tested.