Raza Muhammad Hamid, Di Chio Roberto, Movlaee Kaveh, Amsalem Patrick, Koch Norbert, Barsan Nicolae, Neri Giovanni, Pinna Nicola
Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany.
Department of Engineering, University of Messina, C.Da Di Dio, I-98166 Messina, Italy.
ACS Appl Mater Interfaces. 2022 May 18;14(19):22041-22052. doi: 10.1021/acsami.2c00808. Epub 2022 May 6.
Heterostructures made from metal oxide semiconductors (MOS) are fundamental for the development of high-performance gas sensors. Since their importance in real applications, a thorough understanding of the transduction mechanism is vital, whether it is related to a heterojunction or simply to the shell and core materials. A better understanding of the sensing response of heterostructured nanomaterials requires the engineering of heterojunctions with well-defined core and shell layers. Here, we introduce a series of prototypes CNT-MOS, CNT-MOS, CNT-MOS-MOS, and CNT-MOS-MOS hierarchical core-shell heterostructures (CSHS) permitting us to directly relate the sensing response to the MOS shell or to the p-n heterojunction. The carbon nanotubes are here used as highly conductive substrates permitting operation of the devices at relatively low temperature and are not involved in the sensing response. NiO and SnO are selected as representative p- and n-type MOS, respectively, and the response of a set of samples is studied toward hydrogen considered as model analyte. The CNT-MOS CSHS exhibit response related to the MOS-shell layer. On the other hand, the CNT-MOS-MOS and CNT-MOS-MOS CSHS show sensing responses, which in certain cases are governed by the heterojunctions between MOS and MOS and strongly depends on the thickness of the MOS layers. Due to the fundamental nature of this study, these findings are important for the development of next generation gas sensing devices.
由金属氧化物半导体（MOS）制成的异质结构对于高性能气体传感器的发展至关重要。自从它们在实际应用中的重要性被认识以来，深入了解其转导机制至关重要，无论这是与异质结相关还是仅仅与壳层和核层材料有关。更好地理解异质结构纳米材料的传感响应需要设计具有明确核层和壳层的异质结。在这里，我们介绍了一系列原型CNT-MOS、CNT-MOS、CNT-MOS-MOS和CNT-MOS-MOS分级核壳异质结构（CSHS），使我们能够直接将传感响应与MOS壳层或p-n异质结联系起来。这里的碳纳米管用作高导电基底，使器件能够在相对较低的温度下运行，并且不参与传感响应。分别选择NiO和SnO作为代表性的p型和n型MOS，并研究了一组样品对作为模型分析物的氢气的响应。CNT-MOS CSHS表现出与MOS壳层相关的响应。另一方面，CNT-MOS-MOS和CNT-MOS-MOS CSHS显示出传感响应，在某些情况下，这些响应受MOS与MOS之间的异质结支配，并且强烈依赖于MOS层的厚度。由于这项研究的基础性，这些发现对于下一代气体传感装置的开发很重要。
