Suspended core-shell Pt-PtOx nanostructure for ultrasensitive hydrogen gas sensor

Basu, Palash Kr and Kallatt, Sangeeth and Anumol, EA and Bhat, Navakanta (2015) Suspended core-shell Pt-PtOx nanostructure for ultrasensitive hydrogen gas sensor. In: JOURNAL OF APPLIED PHYSICS, 117 (22).

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Abstract

High sensitivity gas sensors are typically realized using metal catalysts and nanostructured materials, utilizing non-conventional synthesis and processing techniques, incompatible with on-chip integration of sensor arrays. In this work, we report a new device architecture, suspended core-shell Pt-PtOx nanostructure that is fully CMOS-compatible. The device consists of a metal gate core, embedded within a partially suspended semiconductor shell with source and drain contacts in the anchored region. The reduced work function in suspended region, coupled with builtin electric field of metal-semiconductor junction, enables the modulation of drain current, due to room temperature Redox reactions on exposure to gas. The device architecture is validated using Pt-PtO2 suspended nanostructure for sensing H-2 down to 200 ppb under room temperature. By exploiting catalytic activity of PtO2, in conjunction with its p-type semiconducting behavior, we demonstrate about two orders of magnitude improvement in sensitivity and limit of detection, compared to the sensors reported in recent literature. Pt thin film, deposited on SiO2, is lithographically patterned and converted into suspended Pt-PtO2 sensor, in a single step isotropic SiO2 etching. An optimum design space for the sensor is elucidated with the initial Pt film thickness ranging between 10 nm and 30 nm, for low power (< 5 mu W), room temperature operation. (C) 2015 AIP Publishing LLC.

Item Type:	Journal Article
Publication:	JOURNAL OF APPLIED PHYSICS
Publisher:	AMER INST PHYSICS
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre:	Division of Chemical Sciences > Materials Research Centre Division of Electrical Sciences > Electrical Communication Engineering Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	31 Jul 2015 05:13
Last Modified:	25 Feb 2019 05:14
URI:	http://eprints.iisc.ac.in/id/eprint/51918

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