Temperature-Dependent Plasmonic Response of Graphene Nanoresonators

Abstract

Graphene plasmons have attracted enormous research interest due to their dynamic tunability and the extreme field confinement they provide. However, despite their popularity, most studies revolving around graphene plasmons have been restricted to room temperature, leaving unconsidered important tunability knob. In this work, we experimentally investigate the temperature-dependent plasmonic properties of graphene nanoresonators with varying widths on SiO2 substrate by infrared transmission spectroscopy. As temperature drops from 300 to 100 K, the intensity of the graphene plasmon resonance peak increases up to 76%, and the amount of enhancement decreases with increasing carrier concentration and decreasing resonator width. We attribute the enhancement of graphene plasmon resonance to an additional hole doping of Δp = 1.37 × 1012 cm–2 associated with cooling and reduced plasmon damping due to the suppression of phonon-mediated scattering channels. Our results uncover the significance of temperature effects that can be exploited in graphene-based tunable plasmonic devices operating at low temperatures.