NANOMECHANICAL PROPERTIES AND POSSIBLE APPLICATIONS OF MECHANOACTIVATED ZNO COATINGS

A simple and cost-effective mechanoactivated oxidation method (MAOM) has been developed for producing ZnO coatings on glass. To achieve the transparency of initially opaque mechanoactivated ZnO coatings they were annealed at the temperatures modifying the surface morphology of nanostructured coatings. Investigation of nanomechanical properties has revealed that MAOM coatings in as-obtained state have higher hardness (up to 3 GPa) as compared with bulk metallic zinc (160 MPa). In the annealed state the coatings show stabily high adhesion with glass, with the ability to form a grained structure (hardness 8-10 GPa) or a whiskers nanostructure (hardness 18-20 GPa). The Young modulus of coatings ranged from 80 to 120 GPa. The nanomechanical and optical properties were compared with those of bulk ZnO single crystal and commercial ZnO films. The optical properties of ZnO films with a whiskers structure are typical of a transparent high-quality ZnO single crystal. The coatings obtained have high electrical resistance, which decreases in response to the UV exposure. The photocurrent increases by two orders of magnitude, which is easily detectable and makes it possible to use such coatings as UV emission detectors.