Investigation of polished single crystal ZnO by nanoindentation

The near surface mechanical response of polished single crystal ZnO has been investigated by nanoindentation. Surfaces of (0001) ZnO crystals were prepared by mechanical polishing with 1/4 mum and 1 mum diamond abrasives and by chemomechanical polishing. Values for the critical load at the onset of yielding, the elastic modulus and the depth dependent values of hardness were measured. Results were compared to etched (0001) surfaces and (0001bar), {101bar0} and {112bar0} surfaces which had been chemomechanically polished. Surface preparation and crystal orientation were both found to have an effect on the near surface mechanical response.