AVS 58th Annual International Symposium and Exhibition
    Thin Film Division Tuesday Sessions
       Session TF+EN-TuM

Paper TF+EN-TuM10
Angle Dependent Electromotive Force in an Al2o3/Al/Thermoelectric Power Generator System Interacting with Infrared Radiation

Tuesday, November 1, 2011, 11:00 am, Room 107

Session: ALD for Energy
Presenter: Giovanna Scarel, James Madison University
Authors: A.J. Vincent-Johnson, James Madison University
K.A. Vasquez, James Madison University
A.E. Masters, Custom Thermoelectric
X. Hu, James Madison University
G. Scarel, James Madison University
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We present a fundamental study of the interaction between infrared radiation and an Al2O3 film on Al sheet placed on a thermoelectric power generator (system 1). We compare the results with those obtained for a system consisting in an Al sheet on a thermoelectric power generator (system 2). The Al2O3 film in system 1 is prepared using atomic layer deposition, which provides smooth and well defined air/film and film/substrate interfaces. Infrared spectra show that Al2O3 films on the aluminum foil absorb an increasing amount of infrared radiation at increasing angle of incidence. This behavior, known as the Berreman effect, is caused by the radiative surface polaritons excited close to the frequencies of longitudinal optical phonons by the infrared radiation at the interfaces of Al2O3/Al. Our work demonstrates that a similar trend occurs when infrared radiation is absorbed by system 1: as the infrared radiation starts illuminating system 1 in its initial condition, the electromotive force jumps up to a maximum (EMFmax) and then decays exponentially. The EMFmax value and its amplitude increase with the increasing incidence angle of the infrared radiation. Since system 2 exhibits only a weak dependence of the EMFmax value and amplitude on the incidence angle of the infrared radiation, we conclude that the behavior of the electromotive force during the transient in system 1 is caused by radiative surface polaritons in Al2O3/Al. This research is at a seminal stage and needs further understanding. However many routes can be investigated to enhance the efficiency of the electromotive force production. The results are relevant to energy generation from radiation, sensors, and electromagnetic wave detectors.