Nanotribology of single crystal ZnO surfaces: Restructuring at high temperature annealing

Atomic force microscopy is used to study low friction structures formed on single crystal zinc oxide because of annealing. Zinc oxide thin films depos ited in this laboratory showed low friction (similar to 0.2) and long wear life (over one million cycles) in humid air at room temperature. Research i nto, the mechanisms for this low friction behavior, far exceeding the life of typical solid lubricants (e.g., MoS2 and graphite) led to the present wo rk, which focuses on the nanotribology of single crystal ZnO surfaces. Ther mal annealing was used to cause surface reconstruction and defect formation . Etch pits were formed on the (10(1) over bar 0) surface and roughening or reconstruction occurred on the (0001) surface. These pits and roughened ar eas showed low friction that could be originating from interactions of defe cts and restructured crystal faces due to adsorbates. Adhesion and relative contact stiffness were not significantly different between friction contra sting regions. The results of lateral force microscope analysis of the diff erent single crystal surfaces are presented here. (C) 1999 American Vacuum Society.