Aluminum-Doped Zinc Oxide as Transparent Electrode Materials

Pristine and Al-doped zinc oxide nanopowders were synthesized via a surfactant-assisted complex sol-gel method, possessing a pure ZnO phase structure and controllable grain size which was characterized by X-ray diffraction and scanning electron microscopy. Using these nanopowders, the pristine and Al-doped ZnO magnetron sputtering targets were prepared following a mold-press, cold isostatical-press and schedule sintering temperature procedure. The relative density of these as-prepared targets was tested by Archimedes' method on densitometer. All of the results were above 95 theory density percents, and the resistivity was tested on four-probe system at a magnitude of 10(-2) Omega cm. Related pristine ZnO thin films and Al-doped ZnO thin films were fabricated by magnetron sputtering method, respectively. The pristine and Al-doped ZnO films deposited on the quartz glass by dc sputtering owned a (002) orientation with a thickness of 350 nm at a deposition power of 100 W for two hours under an argon plasma. A good optical transparency above 80% and low resistivity of 1.60x 10(-3) Omega cm were obtained with a deposition temperature of 573 K. The optical energy bandgap could be tailored by Al doping at 4 at.% Al.