Aluminum-based hot carrier plasmonics

Abstract

Aluminum has recently arisen as an excellent alternative plasmonic material due to its tunability, low optical loss, and CMOS compatibility. However, its use in optoelectronic applications has been limited due to Al oxidation. Herein, we report a semiconductor-free aluminum hot carrier device that exploits the self-terminating oxidation to create an interface barrier for high performance metal–insulator–transparent conducting oxide devices. We find a 300% enhancement of the responsivity compared to similarly reported Au-based devices, resulting in a responsivity up to ∼240 nA/W, and a clear dependence of the open-circuit voltage on incident photon energy. We show that further improvement can be obtained by coupling to plasmonic modes of a metal-insulator-metal structure composed of a nanowire array adjacent to a thin aluminum film, increasing light absorption by a factor of three and enabling tunability of the hot carrier response for improved device performance.