Compact Modelling of Chirality and Contact Resistance Effects in CNTFETs

This work presents a compact, semi-empirical modelling framework for Carbon Nanotube Field-Effect Transistors (CNTFETs) based on the impact of chiralitydependent electronic properties and contact resistance. The diameters and bandgaps of (10,0), (8,3), and (7,5) CNTs are computed from lattice geometry. The drain current is modelled using a subthreshold formulation coupled with a velocity saturation function. The internal drain bias is solved self-consistently to incorporate series contact resistance. Transfer characteristics and Output characteristics are simulated for all three chiralities, which are used to extract the ON current, OFF current, ON/OFF ratio, and peak transconductance values. Results show that increasing contact resistance significantly reduces the effective channel bias, suppressing ON-state conduction and degrading overall energy performance. The paper provides a computationally efficient approach for evaluating chirality-specific CNTFET behaviour and quantifying the impact of contact engineering on nanoscale device operation.