3D Au nanoparticle lattices in MoO₃ for tunable optical and thermo-electrical properties

Incorporating noble-metal nanoparticles into semiconductors offers a powerful means to tailor their functional properties. Here, we demonstrate that embedding ordered three-dimensional lattices of Au nanoparticles (Au NPs) into MoO₃ thin films via magnetron sputtering enables broad tunability of the optical and thermo-electrical behavior. The formation of regular Au NP lattices, with controlled particle sizes, interparticle separations, and ordering, is achieved through precise adjustment of the deposition temperature and layer thickness conditions. Localized surface plasmon resonances (LSPR) arising from Au NPs-and their coupling at small separations-induce a strong modulation of the optical absorption across a wide spectral range. Simultaneously, the film's electrical resistance can be tuned by up to six orders of magnitude, while the activation energy and temperature coefficient of resistance (TCR) are reduced by up to fifty-fold compared to pure MoO₃. These findings offer relevant information for designing oxide-plasmonic hybrid materials, highlighting their potential for next-generation optoelectronic, sensing, and energy-harvesting devices.