ATOMIC-FORCE MICROSCOPIC OBSERVATION OF M OLYBDENUM TRIOXIDE SURFACE

Surface morphology of MoO3 was observed with an atomic force microscop e. The array of (MoO6)(6-) octahedra was clearly observable for the ox idized surface of a thin crystal prepared by the evaporation-condensat ion process. Similar high resolution AFM image was also obtained for t he powder sample which was coated and dried on the substrate using an ethanol suspension. The high resolution image of the (MoO6)(6-) array disappeared after heating the thin crystal in reducing atmosphere at 3 50-degrees-C, but restored after reoxidation in air at 500-degrees-C. Vacuum deposited MoO3 film on silica glass was amorphous and its surfa ce was smooth and flat after heating at or below 300-degrees-C. The fi lm crystallized on heating at 400-degrees-C accompanying a slight micr ostructural change at the film surface. This film exhibited sharp diff raction lines from (0k0) planes. The thin film morphology was destroye d and changed into randomly oriented particles after heating at 500-de grees-C.