| Problems facing transparent conducting oxides (TCOs) include the lack of a viable p-type TCO, the rising cost of raw materials, and the desire for deposition of high quality films on inexpensive, flexible substrates. This thesis presents studies using dc reactive sputter deposition in three related areas of TCOs: growth of biaxially oriented ZnO on amorphous substrates, high-mobility superlattice structure stability, and p-type TCOs.;Using dual magnetron oblique sputtering (DMOS), biaxial oriented ZnO films have been deposited on amorphous substrates. Conditions to achieve the highest reported degree of orientation were determined: 30° incident angle, high PO2, low TS, and thick films. The smallest {101} X-Ray &PHgr; scan FWHM was ~30° in an as-deposited film. Post deposition annealing at 1000°C in air further improved the orientation, achieving a &PHgr; FWHM of 17°. Biaxially oriented ZnO films on amorphous substrates could eliminate the need for expensive substrates, allow additional device properties such as flexibility into systems, and result in improved electrical properties owing to minimization of grain boundary scattering.;Diffusion coefficients for Mg in ZnO/Zn1-xMgxO:Al superlattices, high mobility-high transparency structures, were found using X-ray diffraction and depth profiling analysis. Two diffusion regimes were observed in the system: an initial faster defect enhanced diffusion followed by slower diffusion over long time intervals. The diffusion coefficients for the slower diffusion regime were determined to be 5.5*10-20 cm2/sec, 1.7*10-19 cm2/sec and 9.5*10-19 cm2/sec at 450°C, 500°C, and 600°C, respectively. These findings can be used to determine thermal processing conditions that will minimize interface broadening.;A route to the highest reported conductivity via PVD (1.8 S/cm) in CuAlO 2, a p-type TCO, was found through examination of the processing-properties relationship of these thin films. To maximize conductivity, films were deposited at temperatures that minimize crystal formation and annealed at the low temperature delafossite phase formation boundary: 700°C.;A correlation between Zn content in partially crystalline ZnCo2O4, a p-type conductor, and its optical and electrical properties was found. Increasing Zn cation content above ~45% causes ZnO formation and has a detrimental effect on conductivity. Maximum conductivity occurs directly before this transition. Mg alloying of this system has been shown to widen the band gap. |
