Cheng Yinfen, Li Zhong, Cheng Liang, Yuan Yuxiao, Xie En, Cao Xiaolong, Xin Zhenqing, Liu Yaoyang, Tang Tao, Hu Xinyi, Xu Kai, Manh Hung Chu, Jannat Azmira, Li Yong Xiang, Chen Hui, Ou Jian Zhen
Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China.
Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology, Nanjing Institute of Technology, Nanjing 211167, China.
ACS Appl Mater Interfaces. 2023 Nov 28. doi: 10.1021/acsami.3c12787.
Due to excellent gas sensing performances, such as high responsivity, good selectivity, and long-term stability, two-dimensional (2D) nonlayered metal oxide semiconductors have attracted wide attention. However, their thickness-dependent gas sensing behaviors are rarely investigated, which is critical in the development of practical 2D sensors. In this work, 2D InO crystals with a range of thicknesses are realized by extracting the self-limited oxide layer from the liquid indium droplets in a controlled environment. A strong thickness-dependent optoelectronic NO sensing behavior at room temperature is observed. While full reversibility and excellent selectivity toward NO are shown despite the thicknesses of 2D InO, the 1.9 nm thick InO exhibits a maximum response amplitude (Δ/ = 1300) for 10 ppm of NO at room temperature with 365 nm light irradiation, which is about 18, 58, and 810 times larger than those of its 3.1 nm thick, 4.5 nm thick, and 6.2 nm thick counterparts, respectively. The shortest response and recovery times (i.e., 40 s/48 s) are demonstrated for the 1.88 nm thick InO as well. We correlate such a phenomenon with the change in the InO band structure, which is influenced by the thickness of 2D crystals. This work provides in-depth knowledge of the thickness-dependent gas-sensing performances of emerging 2D nonlayered metal oxide crystals, as well as the opportunities to develop next-generation high-performing room-temperature gas sensors.
由于具有诸如高响应度、良好选择性和长期稳定性等优异的气敏性能，二维（2D）非层状金属氧化物半导体受到了广泛关注。然而，它们与厚度相关的气敏行为却鲜有研究，而这对于实用二维传感器的开发至关重要。在这项工作中，通过在可控环境中从液态铟滴中提取自限性氧化层，实现了一系列不同厚度的二维InO晶体。观察到在室温下存在强烈的与厚度相关的光电NO传感行为。尽管二维InO的厚度不同，但对NO均表现出完全可逆性和优异的选择性，1.9 nm厚的InO在室温下用365 nm光照时，对10 ppm的NO表现出最大响应幅度（Δ/ = 1300），分别比其3.1 nm厚（18倍）、4.5 nm厚（58倍）和6.2 nm厚（810倍）的对应物大。1.88 nm厚的InO也表现出最短的响应和恢复时间（即40 s/48 s）。我们将这种现象与InO能带结构的变化相关联，其受二维晶体厚度的影响。这项工作为新兴二维非层状金属氧化物晶体与厚度相关的气敏性能提供了深入认识，也为开发下一代高性能室温气体传感器提供了机遇。
