Hydrogen induced metallization of ZnO (11̅00) surface: Ab initio study

• Hydrogen atoms are strongly adsorbed atop surface oxygen atoms at ZnO surface.
• Hydrogen adsorption atop surface Zn atoms is strongly unfavorable.
• Hydrogen atoms are shallow donors leading to surface metallization above critical coverage.

Results of first principles hybrid calculations are presented for hydrogen atoms adsorbed upon non-polar ZnO (11̅00) surface. The energy of surface atomic relaxation, H adsorption energy, electronic density redistribution and modification of the electronic structure are discussed. It is shown that hydrogen is adsorbed mainly on the surface oxygen ions and forms a strong bonding with them (2.7 eV). Adsorption of hydrogen on the surface zinc ions is energetically unfavorable (− 4.4 eV). It also shown that surface hydrogen atoms are very shallow donors, thus, contributing to the electronic conductivity, and ZnO metallization.