Near surface mechanical behavior of bulk ZnO

High crystalline quality bulk ZnO presents possibilities for short wavelength (blue/UV) LEDs and lasers. Despite its technological importance, its mechanical response to loading is not well understood, and mechanical properties data for ZnO is nearly non-existent. The interest in determining near surface mechanical properties is motivated by the need to develop an understanding of the bulk material mechanical response to lattice strains and the resulting stresses introduced by heteroepitaxial films and device structures. Understanding of the effects of substrate surface preparation is also of interest because of its well-known effect on the near surface response to mechanical loading.

We are currently using nanoindentation to investigate the near surface behavior of ZnO to mechanical loading. Surfaces prepared by chemomechanical polishing, mechanical polishing and chemical etching have been studied. We are interested in examining both polar and prismatic surfaces in terms of hardness, elastic modulus and the critical load for the onset of plastic deformation.

Funding provided by:

NSF and OCAST

Relevant publications:

Klopfstein, M.J. and Lucca, D.A., "Observation of Nanoindentation Rosettes on {0001}ZnO using Scanning Kelvin Probe Microscopy", Applied Physics Letters, 87 (2005) 131906.

Lucca, D.A., Klopfstein, M.J., Ghisleni, R., and Cantwell, G., "Investigation of Polished Single Crystal ZnO by Nanoindentation", Annals of the CIRP, 51, (2002) 483-485.