Dual-enhanced Raman scattering sensors incorporating graphene plasmonic nanoresonators

Abstract

Vertically-aligned graphene arrays (VAGAs) are particularly attractive plasma materials that can be integrated with fluorine-doped tin oxide (FTO) substrates to generate multifunctional structures consisting of graphene plasma nanoresonators and VAGA/FTO Schottky heterojunctions that are ideal for doubly-reinforced Raman scattering. Herein, plasma-enhanced chemical vapor deposition (PECVD) is used to grow ultra-clean and size-controllable VAGAs on FTO in situ to use as substrates for surface-enhanced Raman scattering (SERS). The resulting surfaces exhibit excellent photoelectric properties, adsorption capacity, and high specific surface areas. These features enhance the electronic interactions between the VAGA, target molecules, and n-type semiconductor substrate, improving the chemical/charge-transfer effect in the heterojunctions. The hybrid SERS substrates are ultra-sensitive, reusable, low-cost, and highly stable as the VAGA effectively quenches interference from excited states. Our research reveals the effective carrier transfer mechanism acting in the VAGA-FTO heterostructure and improves upon the chemical/charge-transfer mechanism in graphene. It also constitutes a new method for developing ultra-sensitive devices.