Abstract CuO-ZnO p-n junctions were constructed by precipitating CuO nanoparticles on the surface of ZnO nanowires followed by an annealing process. The molar ratio of Cu to Zn in the final composites was controlled by regulating Cu content in the precursor solution. XRD, SEM, TEM, EDS, and XPS were used for the structural characterization of the prepared samples. The results confirmed that the monoclinic CuO nanoparticles were closely and uniformly attached on the surface of the hexagonal ZnO nanowires to form the p-n junctions. Notably, the one-dimensional structure of the host ZnO nanowires was well-maintained during the p-n junction construction process. Five sensors based on CuO-ZnO p-n junction nanowires with different Cu/Zn ratios as well as the pure ZnO nanowires were fabricated and their gas sensing performance was systematically compared. The formation of CuO-ZnO p-n junction effectively enhanced the ethanol sensing properties of the host pure ZnO nanowires. And 5%CuO-ZnO exhibited the highest ethanol response at the operating temperature of 300 °C, which was about 4 times higher than that of the pure ZnO. Several factors and considerations were then discussed for the explanation of the distinct sensing behaviors of these sensors.

中文翻译：

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基于 CuO 修饰的 ZnO 纳米线的 Pn 结用于乙醇传感应用

摘要 CuO-ZnO pn 结是通过在 ZnO 纳米线表面沉淀 CuO 纳米颗粒，然后进行退火工艺来构建的。通过调节前体溶液中的铜含量来控制最终复合材料中铜与锌的摩尔比。XRD、SEM、TEM、EDS 和 XPS 用于制备样品的结构表征。结果证实单斜CuO纳米颗粒紧密均匀地附着在六方ZnO纳米线的表面形成pn结。值得注意的是，主体 ZnO 纳米线的一维结构在 pn 结构建过程中得到了很好的维护。制备了五种基于不同 Cu/Zn 比的 CuO-ZnO pn 结纳米线和纯 ZnO 纳米线的传感器，并系统地比较了它们的气敏性能。CuO-ZnO pn结的形成有效地增强了主体纯ZnO纳米线的乙醇传感特性。并且5%CuO-ZnO在300°C的操作温度下表现出最高的乙醇响应，比纯ZnO高约4倍。然后讨论了几个因素和考虑因素，以解释这些传感器的不同传感行为。