Demonstration of the infrared detection of pyroelectric SnO2–Fe2O3 composite ﬁlms
The infrared (IR) detection capability of SnO2–Fe2O3 composite films is demonstrated. The samples were fabricated on glass substrates via spray pyrolysis at deposition temeratures of 240°C, 300°C, and 370°C. Raman spectroscopy confirmed the presence of SnO2 and Fe2O3 phases in the composite films. UV-Vis spectroscopy revealed that a variation of band gap was evident and was attributed to the segregation of the phases during deposition. It also showed that increasing the deposition temperature widens the direct band gap of the composite, approaching that of crystalline SnO2. Lastly, IR detection was demonstrated with the periodic illumination with IR radiation. The voltage response of the composite showed a maximum peak at 46.52 µV, due to the primary pyroelectric effect, and a plateau at 27.95 µV, due to the secondary pyroelectric effect.