Study of the Terahertz Absorptance in 2D-based Nanoribbon Heterostructures

The Terahertz (THz) frequency holds significant potential across various domains, including communication, security scanning, medical imaging, and the food industry. Graphene, due to its favorable electronic and optical properties, is a promising candidate material for THz applications, although its small bandgap may limit performance. One approach to overcome this limitation involves creating nanoribbon strips of graphene, inducing a larger bandgap through carrier confinement. Alternatively, monolayer MoS
2
exhibits high transmittance in the THz range and possesses a broader bandgap, enhancing graphene absorption. Moreover, through black phosphorus (BP)/dielectric layer stacking on gold, the absorption was reported to reach about 70% at 1THz and increasing the carrier concentration by varying the Fermi level causes a blue shift of the absorption frequency. In our research, we utilized a computational model to compare the THz absorption characteristics of two structures; one is based on infinite MoS
2
/graphene nanoribbons on a SiO
2
substrate, and the second is based on novel combination of nanoribbons of graphene, MoS
2
, and BP. Both structures demonstrated significantly improved absorption, at least twice that of graphene-only nanoribbons, and their absorption frequency proved easily tunable throughout the entire THz range. Additionally, physical nanoribbon size influenced the absorption frequency, while temperature variations minimally affected this parameter, ensuring stability across different temperatures. The level of absorptivity reached 95% efficiency thanks to the inclusion of BP properties. Our findings highlight the potential of these structures as economical, easily manufacturable, and adjustable THz frequency absorbers. Their versatility makes it applicable in various fields.