Stabilization of semiconductor surfaces through bulk dopants

We show by employing density-functional theory calculations (including a hybrid functional) that ZnO surfaces can be stabilized by bulk dopants. As an example, we study the bulk-terminated ZnO (0001̄) 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 find 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. 1 Permanent address: IBM Research—Zurich, 8803 Rüschlikon, Switzerland. 2 Author to whom any correspondence should be addressed. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. New Journal of Physics 15 (2013) 083009 1367-2630/13/083009+11$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft