Vertically-Illuminated, Resonant-Cavity-Enhanced, Graphene-Silicon Schottky Photodetectors

TL;DR

This paper introduces vertically-illuminated, resonant-cavity-enhanced graphene-silicon Schottky photodetectors operating at 1550nm, achieving spectral selectivity and high responsivity for applications in optical communications and sensing.

Contribution

The work demonstrates a novel resonant cavity design that enhances responsivity and spectral selectivity of graphene-silicon Schottky photodetectors at 1550nm.

Findings

External responsivity ~20mA/W

Internal responsivity ~0.25A/W

Spectral selectivity tunable via cavity resonance

Abstract

We report vertically-illuminated, resonant cavity enhanced, graphene-Si Schottky photodetectors (PDs) operating at 1550nm. These exploit internal photoemission at the graphene-Si interface. To obtain spectral selectivity and enhance responsivity, the PDs are integrated with an optical cavity, resulting in multiple reflections at resonance, and enhanced absorption in graphene. Our devices have wavelength-dependent photoresponse with external (internal) responsivity~20mA/W (0.25A/W). The spectral-selectivity may be further tuned by varying the cavity resonant wavelength. Our devices pave the way for developing high responsivity hybrid graphene-Si free-space illuminated PDs for free-space optical communications, coherence optical tomography and light-radars