Amorphous-Carbon/Si Heterojunction Device for Room-Temperature NH3 Sensing

Venkatesh, Eliganti and Singh, Suraj and Tripathy, Suryasnata and Singh, Shiv Govind (2019) Amorphous-Carbon/Si Heterojunction Device for Room-Temperature NH3 Sensing. IEEE Sensors Letters, 3 (2). pp. 1-4. ISSN 2475-1472

Full text not available from this repository. (Request a copy)

Abstract

A room-temperature ammonia (NH3) sensor based on amorphous-carbon/silicon(a-C/Si) heterojunction derived capacitive device is proposed in this article. Herein, controlled pyrolysis of lithographically patterned negative photoresist (SU8) thin films has been performed to realize highly stable a-C/Si junctions. Use of pyrolysis is an economic way of realizing the carbon films, as opposed to the conventional means of sputtering. Additionally, use of the photoresist allows us to preferably pattern the carbon film to develop heterojunction devices of varying shape and surface area. In this study, we have explored the NH3 sensing properties of an unpatterned a-C film based heterojunction, where change in the capacitance-frequency (C-f) response of the heterojunction upon adsorption of NH3 molecules on to the a-C surface is used as the transduction principle. The sensor accounts for a limit of detection (LoD) of 0.26 ppm, a response time of 5-10 s, a postexposure recovery time of 3-5 min, and excellent selectivity, in addition to facilitating room-temperature gas sensing.

[error in script]

IITH Creators: