This paper introduces a novel split gate T-shape channel dielectrically modulated (DM) double-gate tunnel field-effect transistor (DGTFET) with a drain pocket (DP), proposing its application as a label-free biosensor. Through the development and validation of an analytical model using Silvaco TCAD simulation software, the focus is on both the biosensor's sensitivity and its performance as a TFET device. By innovatively shaping the channel, the device demonstrates improved sensitivity, a higher ION/IOFF current ratio, and a reduced sub threshold slope. Notably, the inclusion of the drain pocket at the drain–channel junction effectively eliminates ambipolarity, enhancing ON current performance. Through optimization of the drain pocket length and doping concentration, the device achieves high ON current without ambipolarity. The proposed T-shape DM DPDGTFET surpasses several existing devices in both biosensor and FET device performance. Evaluation of device sensitivity as a label-free biosensor considers the presence or absence of charge in various biomolecules.