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Nanocrystalline sensor-grade Sn1-xInxO2 (0 < or = x < or = 0.2)
K I Gnanasekar1, X Jiang, J C Jiang
1Surface Science, Spectroscopy and Solid State Ionics Laboratory, Department of Physics, Southern University and A&M College, Baton Rouge, Louisiana 70813, USA.
Journal of Nanoscience and Nanotechnology
|August 12, 2003
Summary
Indium doping stabilizes nanocrystalline tin oxide (Sn1-xInxO2), preventing grain growth. Electrical properties change significantly when grain size approaches the Debye length.
Area of Science:
- Materials Science
- Solid State Chemistry
- Nanotechnology
Background:
- Tin oxide (SnO2) is a widely studied material with various applications.
- Controlling the nanostructure of metal oxides is crucial for tuning their properties.
- Indium doping is explored as a method to modify SnO2 characteristics.
Purpose of the Study:
- To prepare and characterize nanocrystalline indium-doped tin oxide (Sn1-xInxO2).
- To investigate the effect of indium doping on the grain size and thermal stability of SnO2.
- To explore the relationship between grain size, Debye length, and electrical properties.
Main Methods:
- Solution chemical route for synthesis of nanocrystalline Sn1-xInxO2.
- High-resolution transmission electron microscopy (HRTEM) for grain size analysis.
- Powder X-ray diffraction (PXRD) and electron diffraction for structural confirmation.
- Thermogravimetric (TG) and differential thermal analysis (DTA) for thermal properties.
- Electrical conductivity and activation energy measurements.
Main Results:
- Nanocrystalline Sn1-xInxO2 (0 ≤ x ≤ 0.2) was successfully synthesized.
- Indium ions stabilize the nanocrystalline structure, limiting grain growth compared to pure SnO2.
- The solid solution decomposes at 820°C, leading to rapid crystal growth.
- Significant changes in electrical conductivity and activation energy were observed when grain size was ≤ 2x Debye length (LD).
Conclusions:
- Indium doping is an effective strategy to maintain the nanocrystalline nature of SnO2.
- The solubility of indium in SnO2 is limited to 20% under investigated conditions.
- Grain size relative to Debye length is a critical factor influencing the electrical behavior of nanocrystalline Sn1-xInxO2.