Chemical and structural factors governing transparent conductivity in oxides

The history, applications, and basic requirements of transparent conducting oxides (TCOs) are reviewed. Four basic families of TCOs are recognized, including n-type oxides with tetrahedrally-coordinated cations (e.g., ZnO), n-type oxides with octahedrally-coordinated cations (e.g., CdO, In2O3, SnO2, and related binary and ternary compounds), p-type oxides with linearly-coordinated cations (e.g., CuAlO2, Cu2SrO2, and related compounds), and n-type oxides with cage structures (e.g., 12CaO.7Al(2)O(3)). TCO behavior is discussed with attention to structural and chemical factors, especially point defect chemistry, governing carrier generation and transport properties.