Growth and characterization of zinc oxide nanowires and thin films.

摘要

ZnO was studied in this dissertation for use in one-dimensional nanoscale devices, optoelectronics, and electronic applications. The synthesis, structural, and optical properties of ZnO and MgO nanowires as nanoscale materials were investigated. The crystallinity, electrical, optical and magnetic properties of undoped and phosphorous doped ZnO thin films for p-type ZnO were examined.; The ZnO nanowires were fabricated using catalyst-driven molecular beam epitaxy. Site specific growth of ZnO and MgO nanowires was observed on Ag coated Si and Al₂O₃ substrates. The structural and compositional studies indicated that the deposition of Zn and Mg resulted in two different types of radial heterostructured (Zn,Mg)O nanowires.; The effect of phosphorus doping on the electrical and optical properties of ZnO grown via pulsed laser beam deposition was studied. Phosphorus doping yields enhanced n-type behavior in as-deposited films, indicating the formation of shallow donor states. Annealing in 100 mTorr of oxygen led to the conversion of n-type behavior in as-deposited films to semi-insulating behavior in the annealed films. For the annealed film, these results appear to reflect phosphorus substitution on the O sites.; The characteristics of device structures that employ phosphorus-doped (Zn,Mg)O have been examined in a effort to delineate the carrier type behavior in this material. The capacitance-voltage properties of metal/insulator/P-doped (Zn,Mg)O diode structures were measured and found to exhibit a polarity consistent with the P-doped (Zn,Mg)O layer being p-type.; The photo-response of ZnO doped with phosphorus was investigated. A correlation between near band-edge emission and carrier density is observed. This is similar to results found for ZnO in which the carrier density is increased via annealing in a reducing ambient. Upon annealing in an oxidizing environment, the near band-edge emission decreased for both the undoped and phosphorus doped ZnO films.; The magnetic properties of phosphorus doped ZnO thin films were examined after high dose Mn implantation. Films show room temperature hysteresis in magnetization loops. The saturation magnetization and coercivity of the implanted single-phase films were both strong functions of the initial annealing temperature. (Abstract shortened by UMI.)