Abstract
Wide band gap based nanostructures have being attracting so much research interest because of their promising applications in optoelectronic devices. This thesis focuses on the growth, optical and electrical properties of GaN and ZnO nanostructures, and their device application in solar cells and light emitting diodes (LEDs). GaN nanowire based dye sensitized solar cell has been studied. Different post-growth treatment has been applied to enhance dye absorption such as annealing and coating of TiOx shell. ZnO nanorods are synthesized by vapor deposition and electrodeposition. Post-growth treatments such as annealing and hydrothermal treatments are used to modify the defect and optical properties of ZnO. LEDs based on GaN/ZnO heterojunctions have been fabricated. The influence of seed layer, shell and different GaN substrates has been studied. It is found that the emission of GaN/ZnO LEDs is most likely originating from GaN substrate. In that case, GaN/ZnO LEDs with MgO as an interlayer have been fabricated to modify the emission mechanism. In addition, nitrogen and cerium doped ZnO devices have been studied, respectively. It is found that the properties of doped ZnO devices can be quite different by using different precursors.