Microstructure and electrical property of aluminum doped zinc oxide ceramics by isolating current under spark plasma sintering

The present paper reports a method for sintering conductive aluminum doped zinc oxide (AZO) ceramics by isolating the current from sample during SPS. It is shown that isolating the current from AZO ceramics during SPS has a significant influence on the grain growth and dislocation defects which dominate the electrical property of ceramics. With isolating the current from AZO ceramics during SPS, the grain size of AZO and a secondary phase ZnAl2O4 is obvious greater than that of samples prepared with current passing through, especially for the sintering temperature of 1200 degrees C. Furthermore, less dislocation defects in AZO ceramics is observed by isolating the current from AZO ceramics. Hall mobility of aluminum doped zinc oxide ceramics has been greatly improved reaching the value of 107.3 cm(2) V-1 s(-1) attributed by the large grain size of ZnO and secondary phase as well as less dislocation defects. The superior electronic transport property with such high vale of Hall mobility ultimately results in a fairly low resistivity of 6.7 x 10(-4) Omega cm compared to 1.3 x 10(-3) Omega cm reported in the literature for AZO fabricated by spark plasma sintering. (C) 2016 Elsevier Ltd. All rights reserved.