Nanocrystalline ITO Research Articles

Sensing Characteristics of Cubic and Rhombohedral Nanocrystalline ITO Thick Films

AbstractTwo kinds of nanocrystalline Tin doped indium oxide (or indium tin oxide: denoted ITO hereafter) powders with different crystal structures – rhombohedral and cubic – were prepared using a coprecipitation method through the control of pH of a mixing solution and aging time after coprecipitation. The two powders have the same particle size of 15 nm in diameter but different morphologies (spherical for rhomboheral and rectangular for cubic). The gaseous ethanol sensing characteristics of the sensors prepared by the two ITO powders were quite different. The sensitivity of rhombohedral ITO sensor was high compared to that of the cubic ITO sensor across all temperatures. The reason for this is explained through the viewpoint of the binding energy of XPS and the surface structure relating to the crystal structure.

Synthesis of Cubic and Rhombohedral Phased Nanocrystalline SnO2 Doped In2O3 [ITO] Powders with Coprecipitation Method

ABSTRACTNanocrystalline ITO powders have been prepared by a hydroxide coprecipitation method. Through the variation of aging time after precipitation, we have characterized the size, morphology and the structure of the precipitates. It was found that the precipitates are in the state of InOOH at first. Further aging up to 48 h changed it to In(OH)3 structure. After calcinations of the precipitates, rhombohedral nanocrystalline ITO powder with spherical shape was produced from InOOH structured precipitates, while cubic nanocrystalline ITO powder was produced from In(OH)3. Fraction of the rhombohedral ITO powder decreased as the aging time increased. The particle size of the cubic ITO increased with aging time but that of rhombohedral ITO (∼15 nm) was almost invariant.