<p>A graphene channel Z-shaped tunnel field-effect transistor (GC-ZTFET) sensor is proposed in this research for detecting hydrogen gas. Faster charge transport and more effective drain current modulation are made possible by graphene’s high carrier mobility and superior electrical conductivity. The unique Z-shaped gate structure efficiently enhances the electric field and interband tunneling rate within the channel region. A palladium metal with a suitable work function is considered as the gate catalyst for better gas sensing. The gas sensor modifies the flat band voltage and capacitance–voltage properties through the adsorption of gas atoms at the interface. This alternately affects the drain current, which is used as a sensing metric. The gas sensitivity is estimated in terms of drain current and current ratio. The suggested gas sensor offers greater sensitivity than TFET and Z-TFET. At HP = 10^–10&#xa0;torr, the GC-ZTFET exhibits a higher peak current sensitivity of 2.86 × 10³, which is seven times and more than one decade higher than the results in the case of Z-TFET and TFET. It also exhibits exceptional sensitivity to very low gas pressures, making it a promising candidate for advanced gas sensor technologies. The sensitivity analysis is also expanded to explore the effects of variation in temperature and trap charge carriers at the catalyst-gate interface.</p>