Document Type : Original Article

Authors

• Elnaz MohammadAlipour ¹
• Daryoosh Dideban ²
• Hossein Karamitaheri ³

¹ Institute of nanoscience and nanotechnology, University of Kashan, Kashan, Iran

² Department of Electrical and Computer Engineering

³ Department of Electronics, Faculty of Electrical and Computer Engineering, University of Kashan, Kashan, Iran

Abstract

This work presents a comprehensive computational study on the thermoelectric evolution of armchair graphene nanoribbons (AGNRs), utilizing a nearest-neighbor Tight-Binding framework within the ballistic transport regime. A comparative analysis of electron transmission spectra for ribbon widths of n=6,7, and 8 identifies the width-8 topology as the optimal platform for strain-induced band engineering, primarily due to its intrinsic gapless metallic nature. Consequently, the research focuses on elucidating the temperature-dependent response (100–700 K) of this optimized width under uniaxial strain. By systematically optimizing the Fermi energy to maximize the power factor, we demonstrate that strain triggers a critical metal-to-semiconductor transition, effectively decoupling electronic thermal and electrical transport channels. A pivotal finding is the thermal modulation of this transition: while cryogenic temperatures (100 K) yield an instantaneous >60-fold enhancement in the electronic figure of merit (ZT_el) at 1% strain, elevated temperatures (700 K) require larger strain thresholds to overcome carrier thermal broadening. Most significantly, the data establishes a distinct electronic performance ceiling, where ZT_el converges to an intrinsic maximum of ≈4.5"-" 4.7 regardless of temperature, positioning strain-engineered 8-AGNRs as robust candidates for high-efficiency thermoelectric applications.

Keywords

• Armchair Graphene Nanoribbons
• Strain Engineering
• Thermoelectric Properties
• Metal-Semiconductor Transition
• Figure of Merit
• Tight-Binding Model