Kucheyev, S. O.Bradby, J. E.Williams, J. S.Jagadish, C.Swain, M. V.2015-09-212015-09-210003-6951http://hdl.handle.net/1885/15586The deformation behavior of bulk ZnO single crystals is studied by a combination of spherical nanoindentation and atomic force microscopy. Results show that ZnO exhibits plastic deformation for relatively low loads (>~4–13 mN with an ~4.2 mm radius spherical indenter). Interestingly, the elastic–plastic deformation transition threshold depends on the loading rate, with faster loading resulting, on average, in larger threshold values. Multiple discontinuities (so called ‘‘pop-in’’ events) in force–displacement curves are observed during indentation loading. No discontinuities are observed on unloading. Slip is identified as the major mode of plastic deformation in ZnO, and pop-in events are attributed to the initiation of slip. An analysis of partial load–unload data reveals values of the hardness and Young’s modulus of 5.060.1 and 111.264.7 GPa, respectively, for a plastic penetration depth of 300 nm. Physical processes determining deformation behavior of ZnO are discussed.3 pages© 2002 American Institute of Physics http://www.sherpa.ac.uk/romeo/issn/0003-6951 Publishers version/PDF may be used on author's personal website, institutional website or institutional repository (Sherpa/Romeo as of 21/9/2015). Publishers version/PDF may be used on author's personal website, institutional website or institutional repository (SHERPA/RoMEO site as of 18/09/15). http://publishing.aip.org/authors/web-posting-guidelines Copyright 2002 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in (Kucheyev, Sergei et al. "Mechanical deformation of single-crystal ZnO". Applied Physics Letters 80.6 (2002): 956-958) and may be found at (https://doi.org/ 10.1063/1.1448175) (Publisher's journal site as of 21/9/2015).bulk ZnO single crystalsdeformation behaviorspherical nanoindentationatomic force microscopyplastic deformation2002-02-1110.1063/1.14481752015-12-11