Hydrothermal Growth of zinc oxide nano-rods doped with manganese

ZnO nanostructures can be grown using a variety of techniques. Using a hydrothermal method, ZnO nanostructures can be produced easily on a large scale due to the low temperature involved. ZnO is a well-studied wide-band gap (3.37 eV) n-type semiconductor material with significant properties such as a large exciton binding energy (60 meV). In this project we have chosen the hydrothermal method to synthesize undoped and manganese doped zinc oxide nanorods at different growth temperatures of {60}^0C, {70}^0C, {80}^0C, and\\ {90}^0C respectively for 20h. We made a seed layer of ZnO on the Si substrate by annealing zinc acetate at {400}^0 C. The morphology of the nanorods was visualised by taking their side and top SEM images. Micro Raman Spectra shows the crystal orientation of the nanorods with respect to substrate and optical Raman-active modes of undoped and doped nanorods. Room-temperature micro-Photoluminescence spectra of nanorods shows the sharp near band emission at 383 nm and broadband defect emission in the visible range. From EPR spectroscopy we find out whether a significant amount of Mn was incorporated into nanorods. Our findings indicate that the presence of Mn in the growth medium results in improved morphology, even though at the lowest growth temperatures there is no clear incorporation of Mn into the nanorods. This implies that the presence of the Mn ions in the group medium is enough to increase the growth rates of ZnO, regardless of whether the ions are incorporated into the crystal or not.