Design and comparative analysis of aluminum-MoS2 based plasmonic devices with enhanced sensitivity and Figure of Merit for biosensing applications in the near-infrared region

Abstract

Aluminum (Al)-Molybdenum Disulfide (MoS2) based plasmonic structures act as excellent biosensors when exploited in the near-infrared region. While Al is economical as well as compatible with the optoelectronic devices, MoS2 is an emerging 2D nanomaterial with the promise of initiating better plasmonic activity. Based on Kretschmann's arrangement, we have explored angular interrogation over four different combinations of heterostructures with Al as the plasmonic metal layer, at a wavelength of 1550 nm. After studying the effect of Al thickness on the conventional configuration, the intermediate layers between the metal layer and the analyte were optimized. Inclusion of graphene along with MoS2 results in better interaction with the sensing medium. The effect of including silicon is also studied for sensitivity enhancement. In addition, a comparative analysis of sensor performances of the proposed devices is presented taking into account the two important parameters i.e. sensitivity as well as the Figure of Merit (FOM). Among the optimized multi-layered MoS2 based configurations, a maximum sensitivity of about 141°/RIU is obtained along with FOM of about 335.13 RIU−1. Finally, the single-stranded DNA sensing on the proposed devices shows that the structures can be used as a highly sensitive refractive index biosensor for bio-medical applications.