Titanium nanofilms applied as microwave absorber

This work is a study on fundamental properties for the application of titanium (Ti) ultrathin films as electromagnetic absorber. Ti films with nanometric thickness were prepared on flexible and rigid substrates. Absorbance of microwave radiation was constant with frequency, and with intensity dependent on thickness of metal film, acting like a broad band absorber. A maximum of 50% absorption was found when Ti thickness was between 20 and 30 nm. Electrical characterization associates the maximum absorbance with sheet resistance values between 210 and 490 Ω, in agreement with classical theory-based analysis. The Ti surfaces exhibited an oxidized 2-dimensional granular/continuous mixed state, what facilitates the adjust of sheet resistance and the absorption of electromagnetic energy for wider range of Ti thickness. An oxidation process becomes prominent at around 140 °C, increasing the amount of the native surface oxide, what can improve the range of thickness for absorption of electromagnetic energy. Graphical abstract