Effects of substitutional doping and vacancy formation on the structural and electronic properties of siligene: A DFT study

•Vacancies and doping strongly affect the electronic properties of siligene.•Si and Ge vacancies enlarge SiGe bangap, being greater the effect for the Ge case.•Si and Ge substitution by a C atom also enlarges the former SiGe bandgap.•Binding energies indicate that all doped siligene sheets are energetically stable.•The siligene monolayers with vacancies and dopant atoms are non-magnetic.