Microscopy of metal oxide surfaces

Elevated temperature scanning tunneling microscopy is used to study oxides that are room temperature insulators but become sufficiently electrically c onducting at higher temperatures to allow imaging to be performed. Atomic r esolution images of NiO, CoO, and UO2 have been obtained in this fashion wh ich allow surface structure and defect determination. To complement the exp eriments, modeling of the electronic surface structure reveals which atomic sites give rise to the contrast observed in the images. Low voltage scanni ng electron microscopy is used to image small equilibrium pores in UO2 sing le crystals to evaluate the surface energy ratio of the (111) to (001) surf aces.