Tin oxide (SnO2)-based thin films were deposited on alumina printed circuit boards via electron beam evaporation to fabricate CO2 gas sensors operating at room temperature. Femtosecond laser surface nanotexturing was applied as a novel approach to optimize key gas sensitivity parameters, including surface roughness and grain size. Raman and X-ray photoelectron spectroscopy revealed that the sensitive layer consists of a 1 µm SnO film with a non-stoichiometric SnO2 upper layer for the as-deposited film. The electronic disparity between these layers forms a native SnO-SnO2 interface, creating a p-n junction that enhances sensor sensitivity. This sensor shows a sensing response ranging from 7 % to 20 % for CO2 concentrations of 1000 to 2000 ppm, and up to 40 % at 5000 ppm. Laser irradiation introduced periodic surface structures (∼ 800 nm), increasing the roughness and the number of active sites for the gas sensing. Although no significant improvements were observed in terms of sensitivity, the fs-laser treated sensor exhibited enhanced stability and reproducibility, indicating its potential for low-energy consumption gas sensing platforms for indoor air quality applications.

中文翻译：

---

基于 SnO2 的工程薄膜，可在室温下实现高效的 CO2 气体传感


通过电子束蒸发将基于氧化锡 （SnO2） 的薄膜沉积在氧化铝印刷电路板上，以制造在室温下运行的 CO2 气体传感器。飞秒激光表面纳米纹理化被用作优化关键气体敏感性参数的新方法，包括表面粗糙度和晶粒尺寸。拉曼光谱和 X 射线光电子能谱显示，敏感层由 1 μm SnO 薄膜和非化学计量 SnO2 上层组成，用于沉积薄膜。这些层之间的电子视差形成天然 SnO-SnO2 界面，形成 p-n 结，从而提高传感器灵敏度。当 CO2 浓度为 1000 至 2000 ppm 时，该传感器的传感响应范围为 7 % 至 20%，在 5000 ppm 时高达 40%。激光照射引入了周期性的表面结构 （∼ 800 nm），增加了气体传感的粗糙度和活性位点的数量。尽管在灵敏度方面没有观察到显着改进，但飞秒激光处理的传感器表现出增强的稳定性和可重复性，表明其在室内空气质量应用的低能耗气体传感平台中的潜力。