Tuning the electronic properties of half- and full-hydrogenated germanene by chlorination and hydroxylation: A first-principles study

The electronic properties of chlorine and hydroxyl-substituted half- and full-hydrogenated germanene were carefully examined based on the first principles calculation. The results reveal that both the concentration and distribution of the substituent greatly affect the electronic properties of germanene. The half-hydrogenated germanene evolves from a magnetic semiconductor to half metal with the increase of chlorine or hydroxyl concentration. The chlorine or hydroxyl decoration on full-hydrogenated germanene does not change the intrinsic electronic structure of direct band gap, but can reduce the band gap with the increase of concentration. Fully hydroxylated and fully chlorinated germanene are semiconductor as fully hydrogenated germanene. Our calculation results demonstrate that the chlorine and hydroxyl can tune the electronic properties of half- and full-hydrogenated germanene differently.