Young's moduli of ZnO nanoplates:: Ab initio determinations

The elastic constants of ZnO nanostructures control their elastic energy and thereby are important to their function in converting strain energy to electricity. This letter presents the size dependence of Young's moduli of ZnO nanoplates, according to density-functional-theory-based ab initio calculations. Our results show that Young's moduli of (0001)/(0001), (1100), and (1120) nanoplates increase as size decreases. For (0001)/(0001) nanoplate, Young's moduli vary discontinuously with size, due to a phase transformation from wurtzite to graphitic structure. Further, our analyses show that the increase of moduli is due to surface stiffening and bulk nonlinear elasticity. (c) 2006 American Institute of Physics.