High sensitivity terahertz sensor based on semiconductor material for biosensing detection

We propose a tri-band metamaterial sensor operating in the terahertz range, structured with a semiconductor–dielectric–semiconductor configuration. Tri-band resonance is produced by this structure at 4.216 THz, 5.210 THz, and 5.770 THz. The physical mechanism underlying these absorption peaks is elucidated through impedance matching theory. The dependence of geometric parameters on the resonant frequency is analyzed based on an LC model. Furthermore, to obtain the best sensitivity, an analysis is conducted on the influence of the analyte thickness change on the sensor performance. Additionally, we analyze the sensing performance parameters within the analyte refractive index range of 1.33 to 1.4. Our findings highlight that, for the third resonant frequency, the sensor achieves maximum sensitivity, Q factor, and figure of merit of 3.3512 THz RIU⁻¹, 432.5, and 261.81 RIU⁻¹, respectively. Notably, given that most biosensing applications are in the refractive index range of 1.33 to 1.4, our sensor offers promising potential for biomedical diagnostics due to its high sensitivity.