<p>In this paper, for the first time, GaN Junctionless FinFET (JLFinFET) has been proposed for the detection of varied breast cancer (Hs578T, MDA-MB-231, MCF-7 and T47D) and non-tumorigenic cell lines (MCF-10A) considering the dielectric modulation principle. The breast cancer cells exhibit distinct dielectric constants when exposed to high frequency radiations. The device analysis has been performed along with the optimization of the device to ensure high efficacy. The sensitivity analysis has also been presented based on Bruggeman’s model which accounts for the presence of both the malignant and non-tumorigenic cell lines in different proportions in a sample of study. The outcomes of this analysis corroborate the stupendous efficacy of the proposed biosensor even at very low concentrations of cancerous cells further expediting the early detection of the onset of the disease. For T47D breast cancer cell lines, the sensitivity based on Switching ratio and Threshold voltage is the maximum and in the order of 10⁶ and 1.925 respectively. The outcomes for T47D have also been compared with the recently reported device structures. An increase in the Switching ratio sensitivity by an order of 10⁶, 10⁴, 10² has been achieved in comparison with JLFET, Step channel JL-TFET (SC-JL-TFET) and Ferroelectric TFET respectively. Furthermore, an enhancement of 542%, 167%, 150% and 80% in the Threshold voltage sensitivity has also been observed in comparison with SC-JL-TFET, Ferroelectric TFET, MoS₂ TFET and JLFET respectively. Moreover, the linearity, selectivity, noise characteristics, response to interference and impact of the charge density of all the breast cells have also been studied. Therefore, the comparative analysis substantiates the astounding efficacy of the reported device for breast cancer diagnosis.</p>