A first-principles study of 1D and 2D C60 nanostructures: strain effects on band alignments and carrier mobility

Abstract

In the breakthrough progress made in the latest experiment Hou et al (2022 Nature 606 507), 2D polymer was exfoliated from the quasi-hexagonal bulk crystals. Bulk polymer with quasi-tetragonal phase was found to easily form 1D fullerene structure with molecules connected by C=C. Inspired by the experiment, we investigate the strain behaviors of 1D and 2D polymers by first-principles calculations. Some physical properties of these low dimensional polymers, including structural stability, elastic behavior, band alignment and carrier mobility, are predicted. Compared with fullerene molecule, 1D and 2D polymers are metastable. At absolute zero temperature, 1D bears a uniaxial tensile strain less than 11.5%, and 2D monolayer withstands a biaxial tensile strain less than 7.5%. At 300 K, ab initio molecular dynamics confirm that they can withstand the strains of 9% and 5%, respectively. Strain engineering can adjust the absolute position of the band edge. In the absence of strain, carrier mobility is predicted to be µ e = 398 and µ h = 322 for 1D polymer, and = 34 and = 1487 for 2D polymer. Compared with other carbon based semiconductors, these polymers exhibit high effective mass, resulting in low mobility.