Observation of surface plasmon polaritons in 2D electron gas of surface electron accumulation in InN nanostructures

TL;DR

This paper demonstrates the existence of surface plasmon polaritons in InN nanostructures caused by surface electron accumulation, revealing potential for THz plasmonic applications through real space mapping and near-field imaging.

Contribution

First real space mapping of surface plasmon fields in InN nanostructures caused by surface electron accumulation, confirming their plasmonic properties and THz frequency behavior.

Findings

Surface plasmon polaritons observed in InN nanostructures.

Surface electron accumulation confirmed by Raman, photoluminescence, and photoemission.

Near-field imaging shows interference fringes and resonance behavior.

Abstract

Recently, heavily doped semiconductors are emerging as an alternate for low loss plasmonic materials. InN, belonging to the group III nitrides, possesses the unique property of surface electron accumulation (SEA) which provides two dimensional electron gas (2DEG) system. In this report, we demonstrated the surface plasmon properties of InN nanoparticles originating from SEA using the real space mapping of the surface plasmon fields for the first time. The SEA is confirmed by Raman studies which are further corroborated by photoluminescence and photoemission spectroscopic studies. The frequency of 2DEG corresponding to SEA is found to be in the THz region. The periodic fringes are observed in the near-field scanning optical microscopic images of InN nanostructures. The observed fringes are attributed to the interference of propagated and back reflected surface plasmon polaritons (SPPs). The observation of SPPs is solely attributed to the 2DEG corresponding to the SEA of InN. In addition, resonance kind of behavior with the enhancement of the near-field intensity is observed in the near-field images of InN nanostructures. Observation of SPPs indicates that InN with SEA can be a promising THz plasmonic material for the light confinement.