Reduced optical losses in refractory plasmonic titanium nitride thin films deposited with molecular beam epitaxy
Krishna Chand Maurya, Vladimir M. Shalaev, Alexandra Boltasseva, Bivas Saha
Abstract
Refractory plasmonic materials that have optical properties close to those of noble-metals and at the same time are environmentally friendly, commercially viable and CMOS-compatible could lead to novel devices for many thermo-photonic applications. Recently developed TiN thin films overcome some of the limitations of noble-metals, as their optical loss is larger than noble metals and conventional methods to deposit TiN films are not compatible for its integration with other semiconductors. In this work, high-quality epitaxial single-crystalline TiN thin films are deposited with plasma-assisted molecular beam epitaxy (MBE) that exhibit optical losses that are less than that of Au in most part of the visible (300 nm – 580 nm) and near-IR spectral ranges (1000 nm - 2500 nm). In addition, a large figure-of-merit for surface plasmon polariton (SPP) propagation length compared to the previously reported TiN films is achieved with the MBE-deposited films.