Electrical detection of graphene plasmons for mid-infrared photodetection and chemical sensing: A computational study

Abstract

Electrical detection of graphene plasmons is important for developing mid-infrared photodetection and sensing applications based on graphene. Here, we theoretically investigate a configuration based on graphene nanoribbons on silicon, forming a series of Schottky junctions. We calculate the heating up of charge carriers in graphene, following plasmon decay, and their thermionic emission across the junctions leading to the generation of photocurrent. We extract an external responsivity up to ≈110 mA/W with a corresponding noise equivalent power ≈190 pW/Hz0.5, specific detectivity D*≈4×106 Jones, and response time ≈12 ns. We further demonstrate how this platform can be used for developing label free chemical sensors, utilizing surface enhanced infrared absorption, where the analyte presence is directly monitored by the photocurrent change. The methods and conclusions derived in this work are applicable throughout the infrared spectrum, where graphene plasmons can be realized.