A new planar BCN lateral heterostructure with outstanding strength and defect-mediated superior semiconducting to metallic properties

S Thomas and MA Zaeem, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 22, 22066-22077 (2020).

DOI: 10.1039/d0cp02973d

Motivated by the recent synthesis of boron-carbon-nitride (BCN) monolayers with different atomic compositions, we propose a novel planar BCN lateral heterostructure with a combination of graphene and hexagonal boron nitride (h-BN) counterparts. Density functional theory (DFT) and classical molecular dynamics (CMD) simulations are integrated to examine the effects of defects (vacancy and Stone-Wales (SW) defects) and temperature on the physical properties of the BCN heterostructure. We found that structures with SW defects possess the lowest (4.10 eV) and those with vacancy defects possess the highest (7.32 eV) defect formation energy. DFT results show that the computed mechanical properties of the pristine and defective BCN are complementary to those of graphene, and CMD results establish that the size effect on mechanical properties is insignificant. DFT calculations also reveal that the pristine and SW defect filled BCN retain the direct semiconducting electronic characteristics, while C and B mono-vacancies interestingly make it a metallic material due to the slight overlapping of the bands at the Fermi level, and the N mono-vacancy causes a small indirect bandgap (0.08 eV). Besides, the presence of defects significantly changes the work function of BCN due to the lattice rearrangement. Herein, we argue that the defect mediated design of BCN heterostructures can provide new opportunities for plausible applications including energy conversion and storage, and high speed optical and electronic devices due to their semiconducting-metallic functionality and superior mechanical properties.

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