RESUMO
Very recently, the 2D form of BeO monolayer has been successfully fabricated [Hui Zhang et al., ACS Nano, 2021, 15, 2497]. Motivated by these exciting experimental results on 2D layered BeO structures, the effect of atom adsorption, substitutional doping and vacancy defects on the electronic and magnetic properties of a hexagonal BeO monolayer have been systematically investigated employing density functional theory-based first-principles calculations. We found out that BeO monolayer is a semiconductor with an indirect band gap of 5.9 eV. Next, a plethora of atoms (27 in total) were adsorbed on the surface of BeO monolayer to tailor its electronic properties. The bond length, work function, difference in charge and magnetic moment were also calculated for all modifications covering the vacancy defects and substitutional doping. The band gap is also supplied for these changes, showing how these adjustments can provide amazing opportunities in granting a variety of options in band gap engineering and in transforming the BeO monolayer from a semiconductor to a dilute magnetic semiconductor or half-metal in view of different applications. The formation energy of the defects was also computed as an important indicator for the stability of the defected structures, when created in a real experiment. We have theoretically demonstrated several possible approaches to modify the properties of BeO monolayer in a powerful and controllable manner. Thus, we expect to inspire many experimental studies focused on two dimensional BeO growth and property tuning, and exploration for applications in advanced nanoelectronics.
RESUMO
Correction for 'Van der Waals heterostructure of graphene and germanane: tuning the ohmic contact by electrostatic gating and mechanical strain' by A. Bafekry et al., Phys. Chem. Chem. Phys., 2021, DOI: 10.1039/D1CP03632G.
RESUMO
The 2D form of the BeO sheet has been successfully prepared (Hui Zhang et al., ACS Nano, 2021, 15, 2497). Motivated by these exciting experimental results on the 2D layered BeO structure, we studied the effect of the adsorption of B atoms on BeO (B@BeO) and substitutional B atoms (B-BeO) at the Be site at different B concentrations. We investigated the structural stability and the mechanical, electronic, magnetic, and optical properties of the mentioned structures using first-principles calculations. We found out that hexagonal BeO monolayers with adsorbed and dopant B atoms have different mechanical stabilities at different concentrations. B@BeO and B-BeO monolayers are brittle structures, and B@BeO structures are more rigid than B-BeO monolayers (at the same B concentration). The adsorption and the formation energy per B atom decrease as the B concentration increases. In comparison, the work function increases when increasing the B concentration. The work function of B@BeO is higher than the corresponding value of B-BeO (at the same B concentration). The magnetic moment linearly increases as the B concentration increases. BeO is a semiconductor with an indirect bandgap of 5.3 eV. The B@BeO and B-BeO structures are semiconductors, except for 3B-BeO (14.2% doped concentration), which is a metal. The bandgap is 1.25 eV for most of the adsorbed atom concentrations. For B-BeO, the bandgap decreases to zero at a concentration of 14.2%. The bandgap of the B-BeO monolayer at different B concentrations is smaller than the corresponding values of the B@BeO monolayer, which indicates that B substitutional doping has a greater effect on the electronic structure of the BeO monolayer than B adsorption doping. We investigated the optical properties, including the dielectric function and absorption coefficient. The results indicate good optical absorption in the range of infrared and ultraviolet energies for the B adsorbed and doped BeO monolayer.