Novel porous aluminum nitride monolayer: a first-principles study

Using ab initio calculations within the density functional theory, we explored the possible structures and properties of porous AlN monolayer materials. Two kinds of porous AlN monolayers (H- and T-) are identified. The phonon dispersion spectra together with the ab initio molecular dynamics simulations demonstrate that these structures are stable. We further show that the H- and T-AlN porous monolayers have well-defined porous nanostructures and high specific surface areas of 2863 m² g^-1 and 2615 m² g^-1 respectively, which is comparable to graphene (2630 m² g^-1), and can be maintained stably at high temperatures (>1300 K). Furthermore, both porous monolayers exhibit semiconductor properties, with indirect band gaps of 2.89 eV and 2.86 eV respectively. In addition, the electronic structures of the porous monolayers can be modulated by strain. The band gap of porous T-AlN monolayer experiences an indirect-direct transition when biaxial strain is applied. A moderate  -9% compression can trigger this gap transition. These results indicate that porous AlN monolayers may potentially be used in future optoelectronic and catalyst applications.