Controllable growth of Al nanorods for inexpensive and degradation-resistant surface enhanced Raman spectroscopy

TL;DR

This paper demonstrates the first controllable growth of aluminum nanorods via physical vapor deposition with oxygen surfactants, achieving significant SERS enhancement and excellent stability over time, offering a cost-effective alternative to traditional noble metal nanostructures.

Contribution

It introduces a novel method for controllably growing Al nanorods using PVD and oxygen surfactants, enabling stable and inexpensive SERS substrates.

Findings

SERS enhancement factor up to 1250

Nearly no degradation after 30 days in ambient conditions

Stable performance after annealing at 475 K for one day

Abstract

Surface enhanced Raman spectroscopy (SERS) has the capacity of detecting trace amount of biological or chemical matter, even single molecules, through the use of metallic nanostructures such as nanorods. Silver (Ag) and gold (Au) nanorods have led to the impressive enhancement of Raman signals, but they are either expensive, degrade fast over time, or suffer from poor sample repeatability. In contrast, Al is much less expensive, and Al nanorods could potentially be resistant to degradation over time due to the protection from native aluminum-oxide layers. Unfortunately, the controllable growth of Al nanorods has not been reported so far. This Letter reports, for the first time, the controllable growth of Al nanorods using physical vapor deposition (PVD); through the use of oxygen (O) surfactants. The enhancement factor of the Al nanorods in SERS is as high as 1250, and shows nearly no degradation after storage in ambient for 30 days or annealing at 475 K for one day.