Abstract

High-temperature thermionics cathodes require materials that combine structural robustness with efficient thermal and electrical transport. This work investigates the effects of laser annealing on the thermionic performance of vertically aligned carbon nanotube (CNT) arrays cathodes. Post-growth annealing at 1100 degrees C enhances crystallinity, as confirmed by reduced Raman ID/IG ratio from 1.02 to 0.49 and improved nanotube ordering with smaller diameters observed by scanning electron microscopy. Under near-infrared laser irradiances up to 11.0 MW/m2, annealed CNTs exhibit higher photo-thermionic emission, improved responsivity, and increased resistance to laser-induced ablation compared to as-grown samples. To probe structural disorder beyond conventional metrics, we introduce a chaos-based electrical characterization using the Rossler chaotic attractor model. Electrical trajectories generated from CNT-CNT and CNT-Si configurations exhibit distinct chaotic signatures that correlate with defect density and crystallinity. This chaos-based electrical approach directly correlates nanoscale structure with emission performance, enabling the development of highly resilient CNT cathodes for extreme optoelectronic environments.