The SnO2-Ga2O3-Sb2O5 laser ablated composite films for gas sensing: Structural and electrophysical studies

The SnO₂-Ga₂O₃-Sb₂O₅ composite films for gas sensing have been prepared via PLD (Pulsed laser deposition). A novel approach of composite films creation via the PLD has been proposed. Structural and electrophysical studies were performed. Films showed polycrystalline structure with homogenous distribution of tin, gallium, antimony and oxygen. The content of tin increases and gallium content in the film decreases with increasing laser energy density. Dependence of the conductivity of the films on temperature in the temperature range 20-390 °C was investigated. Anomalous decrease of conductivity with temperature was shown. Two activation energies for donor sites in tin oxide were calculated: 174 meV for second ionization of oxygen vacancies; 72 meV for ionization of Sb dopant. The response of films to 5 ppm of ethanol is shown to be 1.3-1.4 at temperatures above 300 °C.