Applied Surface Science, Vol.426, 386-390, 2017
Raman, EPR and ethanol sensing properties of oxygen-Vacancies SrTi3-delta compounds
Polycrystalline SrTiO3-delta powders with cubic perovskite phase were prepared by solid-state reaction method followed by the creation of oxygen vacancies delta-thermal activated. The Raman spectroscopic investigation was carried out in a frequency range of 100-2000 cm(-1), and the second-order Raman modes were observed at room temperature. The Electron Paramagnetic Resonance (EPR) results revealed that SrTiO3-delta samples had evident EPR signals that increased significantly with oxygen-vacancy concentra tions. The incorporation of oxygen vacancies was found to decrease the thermal resistivity. Besides, the electrical sensing measurements showed that sensors based on SrTiO2.925 (STO1) and SrTiO2.875 (STO2) exhibited semiconductor behavior, while SrTiO2.75-based sensor (STO3) revealed the introduction of a metallic behavior at low temperature. Furthermore, these measurements confirmed that the resistivity increased after the introduction of the ethanol gas, which indicates that our samples can be considered as sensors for ethanol gas detection. The formation of oxygen vacancies under ethanol exposure at the surface of SrTiO3-delta sensors was evaluated by photoluminescence. (C) 2017 Elsevier B.V. All rights reserved.