In this article, the quantum dots were employed to prepare gas sensing films, whose grain size was controlled up-to twice the Debye length, which is beneficial to investigate the grain size effect within a certain range, on the sensing mechanism and sensing mechanism of the gas sensors, as Debye length is strongly related to barriers of grain boundaries. In order to clarify the relationship of gas sensing mechanism to grain size and Debye length, the grain size of ZnO films were controlled by heating conditions like reaction temperature and reaction time of Zn(OAc)2 and LiOH, while the Debye length was influenced by operating temperature. The sensing ability of ZnO films with different grain sizes were analyzed under different conditions, when employed to H2S gas. Interestingly, the best sensitivity were observed for grain size much closer to two times of the Debye length. In order to investigate this phenomenon, a Debye model of grain size effects has been derived based on the basic chemical reactions between H2S and absorbed oxygen ions on surfaces of ZnO grains. It indicated that the gas sensitivity would reach the highest sensitivity when the grain size is twice the Debye length, which is in full agreement with experiment’s results.

中文翻译：

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基于氧化锌量子点的气体传感器的传感特性及机理


本文采用量子点制备气敏薄膜，其晶粒尺寸控制在德拜长度的两倍以上，有利于研究晶粒尺寸在一定范围内对传感机理和传感机理的影响。气体传感器，因为德拜长度与晶界势垒密切相关。为了阐明气敏机理与晶粒尺寸和德拜长度的关系，ZnO薄膜的晶粒尺寸通过Zn(OAc)2和LiOH的反应温度和反应时间等加热条件来控制，而德拜长度则受到工作温度。分析了不同晶粒尺寸的ZnO薄膜在不同条件下对H2S气体的传感能力。有趣的是，当晶粒尺寸更接近德拜长度的两倍时，观察到最佳灵敏度。为了研究这一现象，基于 H2S 与 ZnO 晶粒表面吸收的氧离子之间的基本化学反应，导出了晶粒尺寸效应的德拜模型。结果表明，当晶粒尺寸为德拜长度的两倍时，气体灵敏度达到最高灵敏度，这与实验结果完全一致。