This paper presents an on-chip plasmonic-catalytic hydrogen sensing concept with a concentration detection limit down to 1 ppm, based on a metal-insulator-semiconductor (MIS) nanojunction operating at room temperature and zero bias. The sensing signal was enhanced by three orders of magnitude with a one-order of magnitude higher response speed compared to non-plasmonic devices. This performance is attributed to hydrogen-induced interfacial dipole charge layer and plasmonic hot electron modulated photoelectric response. The experimental results agree well with theoretical calculations based on a quantum tunneling model. This on-chip combination of plasmonic optics, photoelectric detection, and photocatalysis offers promising strategies for next-generation optical gas sensors.

Long Wen, Zhiwei Sun, Qilin Zheng, Xianghong Nan, Zaizhu Lou, Zhong Liu, David R. S. Cumming, Baojun Li, Qin Chen