A comparative study of semiconductor-based plasmonic metamaterials

TL;DR

This paper explores the potential of semiconductor-based plasmonic metamaterials, specifically transparent conducting oxides, as low-loss alternatives to metals for NIR applications, demonstrating their advantages in various metamaterial designs.

Contribution

It introduces the use of heavily doped oxide semiconductors as tunable, low-loss plasmonic materials for metamaterials, addressing limitations of traditional metal-based components.

Findings

TCOs outperform metals in ENZ applications in the NIR.

Heavily doped oxides exhibit small negative permittivity and low losses.

TCOs enable new designs for surface-plasmon-polariton waveguides and hyperbolic metamaterials.

Abstract

Recent metamaterial (MM) research faces several problems when using metal-based plasmonic components as building blocks for MMs. The use of conventional metals for MMs is limited by several factors: metals such as gold and silver have high losses in the visible and near-infrared (NIR) ranges and very large negative real permittivity values, and in addition, their optical properties cannot be tuned. These issues that put severe constraints on the device applications of MMs could be overcome if semiconductors are used as plasmonic materials instead of metals. Heavily doped, wide bandgap oxide semiconductors could exhibit both a small negative real permittivity and relatively small losses in the NIR. Heavily doped oxides of zinc and indium were already reported to be good, low loss alternatives to metals in the NIR range. Here, we consider these transparent conducting oxides (TCOs) as alternative plasmonic materials for many specific applications ranging from surface-plasmon-polariton waveguides to MMs with hyperbolic dispersion and epsilon-near-zero (ENZ) materials. We show that TCOs outperform conventional metals for ENZ and other MM-applications in the NIR.