Transparent Conducting Oxide Synthesis Of Aluminium Doped Zinc Oxides By Chemical Coprecipitation

Aluminium doped zinc oxides (AZO) are promising replacements for tin doped indium oxides (ITO) but thin films show a wide range of physical properties strongly dependent on deposition process conditions. Submicrometric 1% aluminum doped zinc oxide ceramics (AZO) are examined, prepared by coprecipitation, from Zn(NO3)(2) and Al(NO3)(3) aqueous solutions, sintered at 1200 degrees C and subsequently annealed in 10-16 atm controlled oxygen fugacity atmospheres, at 1000 degrees C. Electrical resistivity diminishes by two orders of magnitude after two hours of annealing and the Seebeck coefficient gradually changes from -140 to -50 mu V/K within 8 h. It is concluded that increased mobility is dominant over the increased carrier density, induced by changes in metal-oxygen stoichiometry.