Ultra-wide bandgap 2D porous oxide monolayers

We present a comprehensive first-principles investigation of novel two-dimensional porous monolayers based on BeO, CdO, MgO, and ZnO, designed as ultra-wide-bandgap semiconductors (UWBG). Three distinct lattice topologies are explored: IGPD (inorganic graphenyldiene), featuring hexagonal arrangements of phenyl and Dewar-benzene-like units; INP (inorganic naphthylene), a tetragonal lattice composed of cyclobutadiene and naphthalene-like motifs; and INPD (inorganic naphthyldiene), a hybrid tetragonal framework combining structural features of IGPD and INP. All monolayers exhibit dynamic and thermal stability, confirmed by phonon dispersion calculations and ab initio molecular dynamics at 300 K. Mechanical analyses reveal that BeO-based lattices possess the highest stiffness and largest band gaps. Conversely, CdO-based structures are softer and more ductile. Bader charge analysis indicates a mixed ionic–covalent bonding character across all systems. The mechanical anisotropy varies according to lattice topology, with INP structures showing enhanced stiffness due to their compact motifs. These findings provide valuable insights into the design of stable, tunable 2D UWBG semiconductors with potential applications in future electronic and optoelectronic devices. • Novel 2D porous Be, Cd, Mg, and Zn oxide lattices with ultra-wide band gaps. • First-principles study reveals stability and mechanical properties of monolayers. • BeO-based lattices exhibit the highest stiffness and the largest band gaps. • Phonon analysis confirms dynamic stability with no imaginary frequencies. • Charge transfer analysis shows a mixed ionic–covalent bonding nature.