Specific Heat Determination of Metallic Thin Films at Room Conditions

Abstract

A methodology to evaluate the specific heat of metallic thin films at constant pressure and 300 K by means of the heating profile is proposed. Changes on the electrical resistance of metallic films after the application of short electric pulses (20–500 μs) are correlated with changes of temperature of the films. Electric pulses are applied on films by an implemented electronic device. A proposed analytical thermal model predicts the correlation between the duration of the electric pulses and the thermal profiles of the film/substrate systems. The analytical thermal model and the measured thermal profiles results are useful to evaluate the specific heat of films. Following this methodology, Au and Al nanofilms evaporated on glass substrates were analyzed. Results indicate that specific heat values of Au films decrease from (229 ± 15) J/kg K to (125 ± 8) J/kg K, and for Al films from (1444 ± 89) J/kg K to (947 ± 53) J/kg K, for film thicknesses from 20 to 200 nm.