Capacitive humidity sensing properties of freestanding bendable porous SiO2/Si thin films

Soobin Park; Jinmyeong Seo; Jungjoon Park; Inseong Hwang; Han-Seung Lee; Hyunsung Jung; Bongyoung Yoo

doi:10.1038/s41598-022-15955-4

Capacitive humidity sensing properties of freestanding bendable porous SiO₂/Si thin films

Sci Rep. 2022 Jul 8;12(1):11689. doi: 10.1038/s41598-022-15955-4.

Authors

Soobin Park¹, Jinmyeong Seo¹, Jungjoon Park¹, Inseong Hwang¹, Han-Seung Lee², Hyunsung Jung³, Bongyoung Yoo⁴

Affiliations

¹ Department of Materials Science and Chemical Engineering, Hanyang University, Ansan, 15588, Republic of Korea.
² Department of Architectural Engineering, Hanyang University, Ansan, 15588, Republic of Korea.
³ Electronic Convergence Materials Division, Korea Institute of Ceramic Engineering & Technology, 101 Soho-ro, Jinju, 52851, Republic of Korea. hyunsungjung@gmail.com.
⁴ Department of Materials Science and Chemical Engineering, Hanyang University, Ansan, 15588, Republic of Korea. byyoo@hanyang.ac.kr.

Abstract

The fabrication of freestanding bendable films without polymer substrates is demonstrated as a capacitive humidity-sensing material. The bendable and porous SiO₂/Si films are simply prepared by electrochemical-assisted stripping, metal-assisted chemical etching, followed by oxidation procedures. The capacitive humidity-sensing properties of the fabricated porous SiO₂/Si film are characterized as a function of the relative humidity and frequency. The remarkable sensing performance is demonstrated in the wide RH range from 13.8 to 79.0%. The sensing behavior of the porous SiO₂/Si film is studied by electrochemical impedance spectroscopy analysis. Additionally, the reliability of the porous SiO₂/Si sensing material is confirmed by cyclic and long-term sensing tests.