<p>This paper presents a Dielectric-Modulated Tunnel FET design, that utilizes the concept of doping-less to effectively minimize leakage currents in the intrinsic regions of Silicon. The physical working mechanism of the proposed device is simulated by Atlas Silvaco TCAD. The proposed device is specifically designed to detect breast Cancer biomolecules (MCF-7) and healthy breast biomolecules (MCF-10&#xa0;A). This functionality comes out through the modulation of its electrical properties by incorporating dual nanocavities within a junction-less Tunnel FET structure. The proposed device contains double gates to increase the sensitivity of the biosensor, with two nanocavities etched under the source electrodes to allow the binding of breast Cancer biomarkers. Upon immobilization of the Cancer cells within the nanocavities, filled initially with air, this changes the dielectric constant, thus modulating the electrical parameters of the device. These modulated parameters have been calibrated for the recognition of breast Cancer cells, which are found to exhibit higher sensitivity. It mainly relies on the dielectric variations of the biomolecules. Sensitivity and ON-state/OFF-state current characterize the performance of the biosensor. The obtained results indicated that the biosensor reaches its highest sensitivity for the MCF-7 breast cancer biomolecule, K = 27.5, with an I_ON/I_OFF ratio = 3.37 × 10⁴, drain current sensitivity of 1.33 × 10⁵, a low subthreshold swing of 38 mV/dec, and a Specificity in the order of 99.92, while also addressing response Time (τ) and Limit of Detection. The proposed device exhibits significantly enhanced sensitivity compared to existing biosensors and is, therefore, highly suitable for array-based screening and diagnosis of Breast Cancer biomarkers.</p>