Cost-Effective and Power-Efficient Memristor-Based H2 Sensor

Abstract

Emerging memristor technology has gained popularity in research for its various applications in computing, memories, and low-power sensing. Gas sensing, an application of memristors, is made possible all thanks to the active oxide layer in memristive devices that undergoes electrical conductivity variations as a response to the presence of a target gas in the surrounding atmosphere. Redox reactions between the metal-oxide layer and gas molecules result in the capture or release of charge carriers, thereby affecting the conductivity of metal oxides. Reduced graphene oxide (rGO) is a semiconductor that is highly sensitive to surface adsorbents and is affected by defects including oxygen functionalities, making it an excellent candidate for gas sensing applications. Accordingly, this work reports on a planar rGO-based memristive gas sensor for hydrogen gas with the structure of Au/rGO/Au designed to operate at room temperature. The fabricated device in its pristine state is electrically characterized to show its memristive behavior depicted by pinched hysteresis in its IV plot. Fresh fabricated devices are tested conventionally by monitoring their resistance under a constant voltage bias in normal atmosphere and in presence of the hydrogen target gas. While conventional testing at room temperature shows the sensors’ quick response, quick recovery, high repeatability, selectivity, and ability to sense different concentrations; the response of the sensor is relatively low. Hence, a new approach for sensing is proposed to take advantage of the memristive nature of the proposed devices, where instead of a constant voltage bias, a voltage pulse is repeatedly applied across the device. The pulse mode testing yields promising results with a much higher response all thanks to the gas-enhanced resistive switching highlighted in this mode of operation.

Date of Award	Apr 2023
Original language	American English
Supervisor	Baker Mohammad (Supervisor)