Characterization of CuO-doped tin dioxide thin films prepared by pulsed-laser deposition for gas-sensing applications

摘要

The influence of doping level of tin oxide films with different amounts of CuO additives (5%, 10%, 15%, and 20%) on structural, optical, and electrical properties is investigated. The films were prepared by pulsed-laser deposition method. X-ray diffraction patterns show the polycrystalline structure for all films with tetragonal phase for SnO_(2)and monoclinic phase for CuO, and no reaction between them. The surface morphology of films was analyzed and it revealed nano-sized grains for samples doped with 10% and 15% CuO. Hall’s effect measurements show increasing conductivity with increase in the CuO ratio and transfer the type of charge carriers from n- to p-type with 20% CuO. The H_(2)S sensing properties are influenced by the CuO ratio in the SnO_(2)films as well as the operation temperature. The SnO_(2)sensor loaded with 10% CuO is extremely sensitive to H_(2)S and the best operation temperature is 50°C, and it exhibits fast response speed of 7 s and recovery time of 20 s for trace level (10 ppm) H_(2)S gas detection.