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Abstract

We show by employing density-functional theory (DFT) calculations
(including a hybrid functional) that ZnO surfaces can be stabilized by bulk dopants.
As an example, we study the bulk-terminated ZnO (0001) surface covered with half
a monolayer of hydrogen. We demonstrate that deviations from this half-monolayer
coverage can be stabilized by electrons or holes from bulk dopants. The electron
chemical potential therefore becomes a crucial parameter that cannot be neglected
in semiconductor surface studies. As one result, we nd that to form the defect-free
surface with a half-monolayer coverage of hydrogen for n-type ZnO, ambient hydrogen
background pressures are more conducive than high vacuum pressures.