Atomic force microscopy was used to measure forces acting on a sharp tungsten tip as it was brought into contact with silica and 30 mol% binary alkali silicate glasses. Experiments were performed in controlled atmospheres and under vacuum. Attractive forces and liquid-layer thicknesses were found to vary markedly between the glasses, and heterogeneity was observed on the binary alkali silicates analyzed in vacuo. Air or wet carbon dioxide exposure resulted in the penetration of the tip into a soft surface layer on the alkali silicates. In addition, liquid layer formation on the alkali silicates was found to be promoted by exposure to water vapor in the order lithium < sodium < potassium. X-ray photoelectron spectroscopy indicated that reaction between the potassium silicate surface and water vapor occurred on exposure to only torr (1 torr = 1.33 X 102 Pa) water. Surface segregation and leaching of potassium occurred under the same conditions.

The scanning tunneling microscope has been used to image and modify the surface of a conducting oxide (Rb(0.3)MoO(3))in ambient atmosphere. Individual octahedral MoO(6) units of the oxide can be imaged, and under certain conditions defects can be created in the surface that are stable in air. The ability to produce nanometer-sized structures on the surface of an oxide is demonstrated and discussed with reference to nanolithographic applications.

Compounds of the formula AxMozOy, known as molybdenum bronzes, display interesting quasi-low-dimensional electronic properties such as anisotropic conduction, superconductivity, and charge-density waves (CDW). Scanning tunneling microscopy studies have been performed on Na0.9Mo6O17, a purple bronze, and Rb0.3MoO3, a blue bronze, demonstrating that they can be imaged in air with near atomic resolution. Surface defects can be created on these bronzes exhibiting varied in-air stabilities. The interpretation of images is discussed with reference to the structures, CDWs, defect creation techniques, and relative defect stabilities.

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