Tuning conducting phases in C3N/C2N heterostructures: applications in thermoelectrics

Abstract

Due to quantum mechanical effects, nanoscale materials possess unusual and desirable properties. In this work, the electronic transport properties of four zigzag C₃N/C₂N hydrogen passivated heterostructures are investigated using density functional theory, including structures with varying C₂N parts while maintaining an equal number of C₃N components in nanoribbons with a width of 12 and 16 atoms. Our results show that the 12-C₃N/C₂N nanoribbon (N-C₃NC₂N-NR) is a metal, suggesting its use as an electrode material. The highest electronic conductance belongs to the 12-C₃NC₂N-NR, with just one C₂N part. The highest Seebeck coefficient, with a value of 1.17 mV K⁻¹, was achieved for the 12-C₃NC₂N-NR with a C₂N part at the center of the ribbon's width for a chemical potential of 0.58 eV, and a temperature of 300 K. Moreover, the 16-C₃NC₂N-NR, which has two C₂N parts, is a narrow bandgap semiconductor with a value of 0.186 eV. Two flat bands close to the Fermi energy are observed for this structure, indicating its potential for diverse applications in electronics and photonics. Metallic nanoribbons show that different orbitals of atoms can be engaged at the Fermi energy, suggesting different responses in sensing applications.