Ting Cheng, Zhongfan Liu, and Zhirong Liu*.
High elastic moduli, controllable bandgap and extraordinary carrier mobility in single-layer diamond.
J. Mater. Chem. C 8 (39), 13819-13826 (2020).
Abstract: Very recently, fluorinated single-layer diamond (called diamane) was successfully prepared for the first time through the conversion of bilayer graphene in a mild way using a chemical vapor deposition approach, which is stable under ambient atmosphere. Herein, we performed in-depth first-principles calculations on fluorinated and hydrogenated diamane. Our calculations reveal that fluorinated diamane is an ultrathin material with a direct-wide bandgap at the G-point, which is 3.86 eV larger than that of hydrogenated diamane, when using the G0W0 method. Such a bandgap could be effectively modulated by applying external strains or introducing fluorine vacancy defects. Besides, their elastic moduli are comparable to that of graphene and higher than those of most other 2D materials. The ideal tensile strength is dictated by soft-mode phonon instability under uniaxial tension and elastic instability under biaxial strain. Most surprisingly, we found that the calculated electron mobility (2732 cm2 V-1 s-1) and hole mobility (1565 cm2 V-1 s-1) in these two diamond-like monolayers are superior to those of III–V semiconductor compounds. Finally, the Raman-active phonon frequencies were characterized to serve as a fingerprint for the experimentally obtained high-quality diamane. These features will provide these materials with great potential for future applications in nano-optics, nanoelectronics, and nano-electromechanical systems.