Physics

A solid solution of wurtzite-structure GaN/ZnO absorbs light in the visible and can photo-split water. The photo-electrons reduce protons to H2 when a co-catalyst is loaded. The photo-holes oxi-dize water into O2 plus protons at the semiconductor-alloy/water interface. Microscopic details of the water oxidation process are unknown. This thesis focuses on water adsorption and oxidation on the surface of pure wurtzite GaN. A separate project on the relative stability of one-dimensional ZnO nanostructures is also in-cluded. The first part of the thesis presents a study of water adsorption iii on wurtzite GaN. The structures and energetics of a water mono-layer adsorbed on the (101̄0) nonpolar surface of GaN are studied computationally using density functional theory (DFT). Water is predicted to adsorb dissociatively, with protons attached to the sur