Hybrid Structure of 2D Layered GaTe with Au Nanoparticles for Ultrasensitive Detection of Aromatic Molecules.

Abstract

Owing to a complex monocline structure and high-density of defects in monocrystalline GaTe, the performance of GaTe-based electronic devices is considerably compromised. Yet, the defects' nature in GaTe could be a merit rather than a shortcoming in other realms. In our work, the density of defects in GaTe films is utilized for a facile decoration of Au nanoparticles (NPs), which allowed us to extend its application potential to the domain of surface enhanced Raman scattering (SERS) for the first time. Two-dimensional (2D) GaTe layered structures are prepared by mechanical exfoliation, and high-density Au NPs are synthesized by immersion of 2D GaTe in HAuCl4 aqueous solution. By varying the immersion time, the sizes and coverage rate of Au NPs on GaTe can be elaborately tuned. Thanks to the defect nature of GaTe, the maximum coverage amounts to 98%. The hereby achieved Au-NPs-2D-GaTe hybrid structure demonstrates outstanding properties as a superior SERS substrate for ultrasensitive detection of R6G aromatic molecules. Remarkably, the enhancement factor reaches up to 1.6 × 104, and the minimum detectable concentration is 10-11 M, undercutting that of recently reported Au-NPs-MoS2 SERS and Au-NPs-graphene SERS substrates which have a similar structure. With superior detection capability and facile preparation, Au-NPs-GaTe SERS substrates can become a perfect choice for the detection of aromatic molecules.