  By using ab inito calculations within Density Functional Theory, we have
explored the possible structures and various properties of porous AlN monolayer
materials. Two kinds of porous AlN monolayer are identified, and the phonon
dispersion spectrum together with the ab inito molecular dynamics simulations
demonstrate that their structures are stable. We further show that these AlN
porous monolayers have well-defined porous nanostructures and even higher
specific surface areas, namely, which can be comparable with graphene, and can
also be maintained evenly at high temperatures. Furthermore, both porous
monolayers exhibit semiconductor properties with 2.89 eV and 2.86 eV indirect
band gap, respectively. In addition, the electronic structures of such porous
monolayers can be modulated by strains. The band gap of porous 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 the porous AlN monolayer may potentially be used for optoelectronic
applications, as well as for underlying catalysts in the future.
