Novel graphene-like two-dimensional bilayer germanene dioxide: electronic structure and optical properties

Using ab initio calculations, we present a two-dimensional (2D) α-2D-germanene dioxide material with an ideal sp³ bonding network which possesses a large band gap up to 2.50 eV. The phonon dispersion curves and molecular dynamics (MD) simulation under the chosen parameters suggest that the novel 2D structure is stable. The dielectric function and absorption spectrum also show the consistent band gap within the electronic structure diagram, suggesting possible application as an ultraviolet light optical detector. The calculated carrier mobility of 4.09 × 10³ cm² V^-1 s^-1 can be observed along the x direction, which is much higher than that of MoS₂ (∼3.0 cm² V^-1 s^-1). Finally, we found that α-2D-germanene dioxide could potentially act as an ideal monolayer insulator in so-called van der Waals (vdW) heterostructure devices. These findings expand the potential applications of the emerging field of 2D α-2D-germanene dioxide materials in nanoelectronics.