Sensitivity Enhancement of Graphene-MoSe2-Based SPR Sensor Using Ti Adhesion Layer for Detecting Biological Analytes

This paper presents a graphene-MoSe2 enhanced surface plasmon resonance (SPR) biosensor which also incorporates a silver (Ag) metallic layer and a titanium (Ti) adhesion layer. The adhesion layer provides chemical stability, and it has been observed that without this layer, the required number of MoSe2 layers is very large to get the incident light energy transferred to the surface plasmon wave. However, with very large number of MoSe2 layers, additional electron energy loss occurs causing higher full width at half-maximum (FWHM) and deterioration of accuracy. Compared to the conventional SPR sensor, the sensitivity of the proposed sensor (215.5 degrees/RIU) is 2.42 times higher while compared to the graphene-based sensor, it is 2.35 times higher. However, quality factor is slightly compromised, being 86% and 88% of conventional and graphene-based sensors, respectively. The sensitivity improvement can be attributed to the enhancement of the field intensity and the penetration depth into the sensing medium leading to larger interaction volume. Because of the large imaginary part of the dielectric constant, the sensitivity improvement by MoSe2 layer also induces broadening of the SPR curves which ultimately leads to the deterioration of quality factor. The proposed sensor's detection ability of biological analytes, such as glucose, stroma of cornea, blood plasma, and DNA templates of hepatitis B virus (HBV), is demonstrated.

Automated summary

This paper introduces a graphene-MoSe2 enhanced SPR biosensor with improved sensitivity compared to traditional SPR sensors and graphene-based sensors, albeit with slightly compromised quality factor. The sensor's detection capability for biological analytes has been demonstrated.