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Modelling and experimental validation of thin-film effects in thermopile-based microscale calorimeters

Bourque-Viens, Alexandre and Aimez, Vincent and Taberner, Andrew and Nielsen, Poul and Charette, Paul G. (2009) Modelling and experimental validation of thin-film effects in thermopile-based microscale calorimeters. Sensors and Actuators A: Physical, 150 (2). 199 - 206.

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Official URL: http://www.sciencedirect.com/science/article/B6THG...

Abstract

Calorimeters can be miniaturized to the point where they can be integrated into platforms such as micro-total analysis systems (μTAS) or lab-on-chip. Models of microscale calorimeters currently fail to account for variations of material properties known to be present in thin films. This study attempts to address this deficiency. Resistivity and absolute Seebeck coefficient of gold and nickel thin films were found to vary linearly with the inverse of film thickness in the submicron range. Thin-film thermopiles composed of gold and nickel were fabricated and their resistance and sensitivity were measured. Our results show that thin-film effects can introduce a 15% decrease in sensitivity (temperature-to-voltage conversion ratio) and a 30% decrease in resolution (smallest resolvable temperature difference). Introducing material properties variation with film thickness into models of thermopile performance resulted in improved estimates. Modelling results suggest that grain boundary scattering is a strong contributor to the observed film-thickness-related change of resistivity and Seebeck coefficient. These observations have implications for improving the design and fabrication of thermopile-based, and other microfabricated, microscale calorimeters.

Item Type:Article
Uncontrolled Keywords:Thermopile; Thin-film; Microscale calorimeter; Modelling; Design
Subjects:Analytical Science > Nanotechnology for sensing and actuating
ID Code:4965
Deposited By:SPI
Deposited On:09 Apr 2009 11:52
Last Modified:09 Apr 2009 11:52

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