Undoped and aluminum-doped ZnO epitaxial films were grown on (001) sapphire substrates by an ion-beam sputtering method with or without the irradiation of oxygen radicals. The effect of oxygen-radical irradiation was notable in the undoped ZnO films when the growth temperature was relatively low. The irradiation improved the crystallinity and decreased the oxygen-vacancy concentration, while it induced internal stress into the films. The carrier concentration of the undoped ZnO films was decreased by the oxygen-radical irradiation, which was attributable to a decrease in the oxygen-vacancy concentration. The Hall mobility of the undoped ZnO films was as low as 1–3 cm2 V-1 s-1. The low mobility was explained by carrier scattering due to the potential barriers at the grain boundaries. The height of the potential barriers at the grain boundaries decreased with increasing carrier concentration. This behavior was well explained by a simple model assuming a single defect state at grain boundaries.

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Thin films of ZnO and NiO and their superlattices were made by an ion beam sputtering technique. The dielectric functions of these films were measured as a function of photon energy using a variable-angle spectroscopic ellipsometer. Artificial superlattices were formed in [(NiO) 12 / (ZnO) 6 ] 10 , [(NiO) 6 /(ZnO) 4 ] 16 , and [(NiO) 7 /(ZnO) 8 ] 12 films, where ZnO had the rock salt structure rather than the wurtzite type of structure. The dielectric functions of these superlattices were markedly different from those of pure ZnO, NiO, and their mixtures. However, ZnO had the wurtzite type of structure in [(NiO) 10 /(ZnO) 20 ] 4 . In this film, the epitaxial relation which enables the formation of an artificial superlattice was not observed between ZnO and NiO layers, and the dielectric function could be interpreted as a simple mixture of ZnO and NiO.

A non-prism laser measurement system using image control is described. The device combines imaging, nonprism laser measurement, and compute rcontrol techniques to achieve an early understanding of topography and the amount of earthworks required as well as improved work safety. Consisting of CCD cameras, non-prism laser measurement equipment, rotational positioning equipment, and a computer, it is operated interactively using akeyboard or mouse. The laser is of the lowest powerclass, at less than 0.16 mW output, but allows measurement atdistances up to 500 m with a precision of 1 cm. The system is currently in use during site preparation work for the Anan Converter Substation of Shikoku Electric Power Company, where it is assisting in the early understanding of changes in earth volume and topographical control. Receiving of images Setting of ranges Control of units Calculation On-line or off-line Data analyzer (Earth work management system :" LANDY") Reception of data Analysis Preparation of drawing Ultrasonic motor and encoder