First-principles study of the polar O-terminated ZnO surface in thermodynamic equilibrium with oxygen and hydrogen

Abstract

Using density-functional theory in combination with a thermodynamic formalism we calculate the relative stability of various structural models of the polar O-terminated (000-1)-O surface of ZnO. Model surfaces with different concentrations of oxygen vacancies and hydrogen adatoms are considered. Assuming that the surfaces are in thermodynamic equilibrium with an O2 and H2 gas phase we determine a phase diagram of the lowest-energy surface structures. For a wide range of temperatures and pressures we find that hydrogen will be adsorbed at the surface, preferentially with a coverage of 1/2 monolayer. At high temperatures and low pressures the hydrogen can be removed and a structure with 1/4 of the surface oxygen atoms missing becomes the most stable one. The clean, defect-free surface can only exist in an oxygen-rich environment with a very low hydrogen partial pressure. However, since we find that the dissociative adsorption of molecular hydrogen and water (if also the Zn-terminated surface is present) is energetically very preferable, it is very unlikely that a clean, defect-free (000-1)-O surface can be observed in experiment.

arXiv comment10 pages, 4 postscript figures. Uses REVTEX and epsf macros

References in corpus (6)

• Composition, structure and stability of RuO_2(110) as a function of oxygen pressure
• Density-functional study of the structure and stability of ZnO surfaces
• The hematite (alpha-Fe_2 O_3) (0001) surface: evidence for domains of distinct chemistry
• Ab initio study of BaTiO3 and PbTiO3 surfaces in external electric fields
• Ab-initio study of BaTiO3 surfaces
• Edge Electron Gas

Cited by in corpus (14)

• Composition, structure, and stability of the rutile TiO_2(110) surface: oxygen depletion, hydroxylation, hydrogen migration and water adsorption
• Density-functional study of Cu atoms, monolayers, and coadsorbates on polar ZnO surfaces
• Space Charge Transfer in Hybrid Inorganic/Organic Systems
• Tuning surface metallicity and ferromagnetism by hydrogen adsorption at the polar ZnO(0001) surface
• Ideal, Defective, and Gold--Promoted Rutile TiO2(110) Surfaces: Structures, Energies, Dynamics, and Thermodynamics from PBE+U
• Stabilization Mechanism of ZnO nanoparticles by Fe doping
• Effects of ferroelectric polarization on surface phase diagram: an evolutionary algorithm study of the BaTiO${}_3$(001) surface
• A Hybrid Density Functional Study of Oligothiophene/ZnO Interface for Photovoltaics
• Counterintuitive Reconstruction of the Polar O-Terminated ZnO Surface With Zinc Vacancies and Hydrogen
• Modification of anatase TiO${}_2$(001) surface electronic structure by Au impurity
• Hydrogen Surfactant Assisted Coherent Growth of GaN on ZnO Substrate
• Presence of a (1x1) oxygen overlayer on bare ZnO(0001) surfaces and at Schottky interfaces
• Tuning the workfunction of ZnO through surface doping with Mn from first-principles simulations
• The Origin of Two-dimensional Electron Gas in Zn${}_{1-x}$Mg${}_x$O/ZnO Heterostructures