Sensitive thin film layers of SnO 2 , SiO 2 and SiO 2 –SnO 2 were deposited on a surface acoustic wave resonator using sol-gel method and spin coating techniques. Their ammonia-sensing performance operated at room temperature was characterized and their sensing mechanisms were comprehensively studied. When exposed to ammonia, the sensors made of SnO 2 and SiO 2 –SnO 2 films exhibit positive frequency shifts, whereas the SiO 2 film sensors exhibit a negative frequency shift. The positive frequency shift is related to the dehydration and condensation of hydroxyl groups, which makes the films stiffer and lighter. The negative frequency shift is mainly caused by the increase of mass loading due to the adsorption of ammonia. The gas sensor based on SiO 2 –SnO 2 film shows a positive frequency shift of 631 Hz when it is exposed to ammonia with a low concentration of 3 ppm, and it also shows...

中文翻译：

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基于室温工作的SiO 2 -SnO 2复合膜的声表面波氨传感器

利用溶胶-凝胶法和旋涂技术在表面声波谐振器上沉积了敏感的SnO 2，SiO 2和SiO 2 -SnO 2薄膜层。表征了它们在室温下的氨感测性能，并对它们的感测机理进行了全面研究。当暴露于氨气中时，由SnO 2和SiO 2 -SnO 2薄膜制成的传感器呈现出正频移，而SiO 2薄膜传感器呈现出负频移。正频移与羟基的脱水和缩合有关，这使薄膜更硬，更轻。负频移主要是由于氨的吸附导致质量负荷增加。