Titanium Nitride based multi-functional thin films

Abstract

Abstract The aim of the present work is to demonstrate that the applications of TiN thin films can be expanded well beyond the traditional domains. For example, although TiN is known to exist in several sub-stoichiometric forms their properties have not been exploited fully. Using a patented sputtering process technology, we show that the Ti2N phase is semiconducting, possesses a band gap of the order of 3.5eV and a hardness in the region of 5-7 GPa. Thisimplies that Ti2N thin films can be candidates for light emitting diode applications. In some cases, reflectivity <2% in the visible region was also achieved which is useful for optical shielding applications. The nitrogen stoichiometry and thickness of TiN thin films can be tuned to achieve colours from blue to brown to golden yellow for decorative coating applications. TiN thin films can be a cost-effective replacement for Au since they also display a surface plasmon resonance at the same wavelength. The conductivity of TiN is sufficiently high to replace gold as an electrode material in electronic devices such as diodes. The properties of TiN-Si3N4 and TiN-Polyaniline composite thin films are also reported. The current work, thus, demonstrates the multi-functionality of TiN as an optical, opto-electronic and electronic material.