Plasmonics with two-dimensional semiconductors: from basic research to technological applications

Abstract

Herein, we explore the main features and the prospect of plasmonics with two-dimensional semiconductors. Plasmonic modes in each class of van der Waals semiconductors have their own peculiarities, along with potential technological capabilities. Plasmons of transition-metal dichalcogenides share features typical of graphene, due to their honeycomb structure, but with damping processes dominated by intraband rather than interband transitions, unlike graphene. Spin-orbit coupling strongly affects the plasmonic spectrum of buckled honeycomb lattices (silicene and germanene), while the anisotropic lattice of phosphorene determines different propagation of plasmons along the armchair and zigzag directions. Black phosphorus is also a suitable material for ultrafast plasmonics, for which the active plasmonic response can be initiated by photoexcitation with femtosecond pulses. We also review existing applications of plasmonics with two-dimensional materials in the fields of thermoplasmonics, biosensing, and plasma-wave Terahertz detection. Finally, we consider the capabilities of van der Waals heterostructures for innovative low-loss plasmonic devices.

The Optical Properties and Plasmonics of Anisotropic 2D Materials

“…The discovery of electrical tunable and highly confined plasmons in graphene have stimulated considerable efforts to explore new plasmonic 2D materials . Plasmons in 2D materials with in‐plane anisotropy have recently attracted increasing attention due to the possibility of realizing in‐plane hyperbolic plasmon polaritons, the iso‐frequency contour of which is a hyperbola .…”

Emerging Applications of Elemental 2D Materials

“…While the plasmons in semiconducting 2D materials (graphene, phosphorene, and so on) appear in the mid/near‐infrared frequency range (and generally only upon doping), plasmons in intrinsically metallic 2D materials such as borophene can extend into the visible range due to their higher carrier concentrations . In addition, the plasmon dispersion in 2D materials is affected heavily by structural anisotropy (as in the case of buckled and puckered 2D materials), electron density, spin–orbit interaction and strain; in‐depth reviews on plasmonic properties of several 2D materials can be found elsewhere . An example of how structural anisotropy affects the plasmon dispersion is shown in Figure a.…”

“…[45] In addition, the plasmon dispersion in 2D materials is affected heavily by structural anisotropy (as in the case of buckled and puckered 2D materials), electron density, spin-orbit interaction and strain; in-depth reviews on plasmonic properties of several 2D materials can be found elsewhere. [178][179][180] An example of how structural anisotropy affects the plasmon dispersion is shown in Figure 7a. Phosphorene exhibits anisotropic electron masses depending on the crystal orientation, with the electron mass higher (lower) along the zigzag (armchair) direction.…”

Energy loss spectrum and surface modes of two-dimensional black phosphorus

“…Exploration of new 2D plasmonic building blocks in novel material systems is highly desirable to advance the field of plasmonics. As a result, a number of 2D materials in addition to graphene have been successfully prepared, including hexagonal boron nitride, transition metal dichalcogenides, and black phosphorus (BP) [4][5][6]. Among these emerging 2D systems, BP is one of the most promising candidates because of its remarkable electronic and photonic properties, such as its high carrier mobility (5200 cm 2 V −1 s −1 at room temperature), thickness-dependent direct bandgap, and gate-tunable optoelectronic properties [7][8][9][10].…”