Hot carrier devices using visible and NIR responsive titanium nitride nanostructures with stoichiometry variation

In this study, we have synthesized spectrally tuneable titanium nitride (TiN) nanostructures as an alternative to conventional plasmonic materials by pulsed DC reactive magnetron sputtering. With the variation of the stoichiometry of the samples as well as by changing size, and distribution of TiN nanoparticles, tuning of Localised Surface Plasmon Resonance (LSPR) band from visible to near-infrared (NIR) region is observed where stoichiometry plays the major role. These nanostructures are incorporated in photodetector device geometry and photocurrent generated by the hot holes in TiN/CuO system is measured. Two devices - one operating in the visible region and the other operating in the NIR region are fabricated. Photoelectrical study reveals that the photo-induced current is generated by the hot carriers which are produced through the nonradiative decay of plasmons occurring on the surface of TiN nanoparticles. This study demonstrates that there is a strong prospect of plasmonic TiN nanoparticle-based infrared photodetector which may overcome the limitations of conventional infrared detectors e.g. requirement of expensive narrow band-gap semiconductors and other associated issues.