Cho Minkyu, Kim Taehwan, Cho Incheol, Gao Min, Kang Kyungnam, Yang Daejong, Park Inkyu
Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Langmuir. 2022 Jan 25;38(3):1072-1078. doi: 10.1021/acs.langmuir.1c02643. Epub 2022 Jan 7.
Developing high response hydrogen sensors manufacturable in a large scale is desirable in hydrogen industry. In this study, a chromium oxidation-based nanogap formation process was developed to fabricate a hydrogen switch with suspended palladium and gold films having a tens of nanometer-sized gap. The nanogap was formed by using oxidized chromium as a self-alignment shadow mask. The hydrogen switch operates by the principle of volume expansion of palladium upon exposure to the hydrogen gas and the current reading by closing of a nanogap formed between suspended palladium and gold films. Further improvement of the sensor performance was achieved by optimizing the design parameters such as suspended film lengths and thicknesses. The fabricated palladium nanogap hydrogen sensor showed an ultrahigh sensitivity of Δ/ > 10 with a fast response time (22 s) to 4% hydrogen. The complementary metal-oxide-semiconductor-compatible fabrication of the hydrogen switch is easily scalable with low manufacturing cost.
在氢能产业中，开发可大规模制造的高响应氢传感器是很有必要的。在本研究中，开发了一种基于铬氧化的纳米间隙形成工艺，以制造一种氢开关，该开关具有悬浮的钯和金膜，其间隙尺寸为几十纳米。通过使用氧化铬作为自对准荫罩形成纳米间隙。氢开关的工作原理是钯在暴露于氢气时发生体积膨胀，以及通过闭合悬浮钯和金膜之间形成的纳米间隙来读取电流。通过优化诸如悬浮膜长度和厚度等设计参数，进一步提高了传感器性能。所制造的钯纳米间隙氢传感器对4%氢气表现出超高灵敏度（Δ/ > 10）和快速响应时间（22秒）。这种氢开关的互补金属氧化物半导体兼容制造工艺易于扩展，且制造成本低。
