Water Adsorption on the GaN (10(1)over-bar0) Nonpolar Surface

We present a first-principles study of water adsorption on a wurtzite GaN (10 (1) over bar0) surface. We studied the structures and energetics of water adsorption, calculated the energy barrier for water dissociation, and analyzed the water-water interactions. The results are very different from water adsorption on ZnO (10 (1) over bar0). Water is found to adsorb dissociatively; the energy barrier for the dissociation is negligible. As a result of substrate strain-mediated interactions and hydrogen bonding, dense island agglomerates are energetically favored at submonolayer water coverage.