| AVS 57th International Symposium & Exhibition | |
| Energy Frontiers Topical Conference | Friday Sessions |
| Session EN+SS-FrM |
| Session: | Photocatalysis and Solar Fuels |
| Presenter: | H. Schmidt, University of Delaware |
| Authors: | H. Schmidt, University of Delaware D.J. Doren, University of Delaware V.B.R. Boppana, University of Delaware R.F. Lobo, University of Delaware |
| Correspondent: | Click to Email |
Solid solutions of GaN and ZnO have been shown to be a promising class of photocatalysts, capable of splitting water under visible-light irradiation. The structural and electronic properties of Ga1-xZnxN1-xOx have been studied using density-functional theory with the Linear Augmented Plane Wave (LAPW) method at varying values of x. A GGA+U approach is used to better describe the semicore 3d states of Ga and Zn. These calculations show that there exists a p-d coupling between the N 2p and Zn 3d states, leading to a decreased band gap. The band gaps in the mixed metal oxynitrides are lower than either ZnO or GaN, thus allowing excitation by visible light. The trend in band gaps over the range of Zn concentrations (x) is consistent with experimental results. The expected band gap minimum is at a composition that is difficult to synthesize. Formation energies have been calculated to understand the limitations on synthesis of these materials. Several starting materials and synthesis environments have been studied in the formation energy calculations to determine how the thermodynamically preferred products depend on experimental conditions and whether high concentrations of zinc can be obtained in these materials.