In this paper, a double-junction n+/n−/n+ polysilicon nanobelt selectively functionalized with platinum has been studied for hydrogen sensing application. The selective modification of the devices is performed by the combination of localized ablation of a resist and a lift-off process of e-beam evaporation of a catalyst material. The coverage of a Pt layer on the n− region is precisely controlled by adjusting Joule heating bias and pulse length. The Pt-functionalized devices show a rapid response to hydrogen with a limit of detection of only 5 ppm. The device with fully Pt-covered n− region is optimum for obtaining the best response to hydrogen.

Double junction n + /n -/n + polysilicon nanobelt selectively modified with platinum has been studied for hydrogen sensor application. The selective modification of the devices is performed by the combination of localized ablating of a resist and lift-off process of e-beam evaporation of catalyst material. The coverage of Pt layer on nis precisely controlled by adjusting the Joule heating pulse bias and length. The fast response has been observed for hydrogen with the limit of detection of only 5 ppm on devices with Pt fully cover nregion.