Dual-channel microcantilever heaters for volatile organic compound detection and mixture analysis.

Ifat Jahangir,Goutam Koley

doi:10.1038/srep28735

Ifat Jahangir, Goutam Koley

Open Access

https://doi.org/10.1038/srep28735

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Abstract

We report on novel microcantilever heater sensors with separate AlGaN/GaN heterostructure based heater and sensor channels to perform advanced volatile organic compound (VOC) detection and mixture analysis. Operating without any surface functionalization or treatment, these microcantilevers utilize the strong surface polarization of AlGaN, as well as the unique heater and sensor channel geometries, to perform selective detection of analytes based on their latent heat of evaporation and molecular dipole moment over a wide concentration range with sub-ppm detection limit. The dual-channel microcantilevers have demonstrated much superior sensing behavior compared to the single-channel ones, with the capability to not only identify individual VOCs with much higher specificity, but also uniquely detect them in a generic multi-component mixture of VOCs. In addition, utilizing two different dual channel configurations and sensing modalities, we have been able to quantitatively determine individual analyte concentration in a VOC mixture. An algorithm for complete mixture analysis, with unique identification of components and accurate determination of their concentration, has been presented based on simultaneous operation of an array of these microcantilever heaters in multiple sensing modalities.

Highlights

Volatile organic compounds (VOCs) detection system, currently there is no existing technology that is at the same time portable, energy efficient and capable of rapid, sensitive and unique detection of VOCs, especially in multi-analyte mixtures, without any functionalization layer
These dual channel microcantilever heaters (DC-MH) combine the modalities offered by the triangular microcantilever heater (TMH) with novel sensing mechanisms based on heat transfer between the channels interacting with the VOC vapors
Since both channels are physically connected by the GaN layer, we call it monolithic tip dual channel microcantilever heater (MDC-MH)

Summary

Introduction

VOC detection system, currently there is no existing technology that is at the same time portable, energy efficient and capable of rapid, sensitive and unique detection of VOCs, especially in multi-analyte mixtures, without any functionalization layer. The present work introduces dual channel microcantilever heaters where two conducting channels are constructed on the same cantilever to combine multiple modes for detecting VOCs with higher degree of specificity and selectivity These dual channel microcantilever heaters (DC-MH) combine the modalities offered by the triangular microcantilever heater (TMH) with novel sensing mechanisms based on heat transfer between the channels interacting with the VOC vapors. Using these cantilevers in an array, it is possible to detect each compound in a mixture of VOCs along with its approximate concentration. While a lower limit of detection of 5 ppm have been experimentally established, actual limit is expected to be lower than 1 ppm limited by the noise in these devices

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