MICROMORPHOLOGY STUDY OF MERCURIC IODIDE-CRYSTALS BY ATOMIC-FORCE MICROSCOPY

Atomic force microscopy was used to study the surfaces of mercuric iod ide crystals at ambient. Various surface conditions were examined, inc luding as-grown (001), (110), and (013) faces, and cleaved, chemically etched, vacuum etched, and aged (001) surfaces. As-grown (001) faces show a terraced structure and are smoother than as-grown (110) faces. Freshly cleaved surfaces exhibit a terraced structure, with riser heig hts corresponding to multiples of the c-lattice constant. All surfaces become progressively pitted and rougher by vacuum treatment or chemic al etching. Defects identified as pits or hillocks with dimensions of the order of 100 nanometers were also observed, and surface roughness values were obtained for quantitative characterization of the various treatments.