The microstructure of ${\mathrm{SnO}}_2$, prepared by the sol-gel method, was studied by scanning electron microscopy, transmission electron microscopy, high-resolution electron microscopy, and x-ray diffraction. A nanosponge structure was observed. There is much surface and interface structure. The interfaces vary in type from amorphous to crystalline. The high density of defects greatly influences the physical and chemical properties of this material.

• Received 9 November 1993

DOI:https://doi.org/10.1103/PhysRevB.49.14282