Non-ideal subthreshold swing in aligned carbon nanotube transistors due to variable occupancy discrete charge traps

2025/07/18 by Saurabh S. Sawant, Sawant, Saurabh S., Teo Lara +7
Engineering · Materials Science · Physics and Astronomy · #70-08 #81-10 #Applied Physics (physics.app-ph) #Carbon Nanotubes in Composites #FOS: Physical sciences #I.6.3 #J.2 #Mechanical and Optical Resonators #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Nanowire Synthesis and Applications

paper · pdf · doi:10.48550/arxiv.2507.18646

openalex publication_date 2025/07/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

Carbon nanotube transistors have been experimentally demonstrated to reach performance comparable and even surpassing that of silicon transistors. Further improvement requires addressing non-idealities arising from device fabrication that impact performance and reproducibility. One performance metric that determines energy efficiency is the subthreshold swing which is often observed to be 3-4 times larger than the ideal thermal limit. In this work, we present simulations indicating that a discrete number of variable occupancy hole trapping sites can explain the large subthreshold swing. Our simulations indicate that while three-dimensional trap distributions influence the subthreshold swing, only the traps in close proximity to the nanotubes have a significant impact. The results suggest that a density of trapping sites on the order of 0.5/nm² near the nanotubes is sufficient to significantly increase the subthreshold swing, requiring the removal or passivation of only a few sites per carbon nanotube.

Citations

• ELEQTRONeX: A GPU-Accelerated Exascale Framework for Non-Equilibrium Quantum Transport in Nanomaterials
• Physics of Semiconductor Devices (2nd edn)

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