Site-Selective Atomic Layer Deposition for Surface Defect Amelioration

While ALD is most commonly employed in uniform conformal growth, more selective precursors and processes may allow for more precise synthetic strategies including targeted reaction at subtly unique surface sites including those that lead to electronic defects. The adsorption free energies for molecular and dissociative adsorption of H₂O on TiO₂ and In₂O₃ were calculated to evaluate this strategy as a viable route to step edge and oxygen vacancy selectivity. We predict that selective hydroxylation is possible on several step edges and vacancy sites and further computationally evaluate three metalorganic ALD precursors for their compatibility with the selective hydration strategy. Experimental evidence for delayed nucleation of ALD on rutile (001), (110), and (100) TiO₂ single crystals corroborates predictions of surface dehydration that enables site-selective synthesis.