Structural, mechanical, and electronic properties of ultrathin ZnO nanowires

We report a structural transformation between the regular wurtzite and the unbuckled wurtzite (hexagonal) structure for ultrathin single-crystalline [0001] ZnO nanowires under uniaxial elongation and compression. Our density functional calculations show that hexagonal structure corresponds to a distinct minimum on the transformation path. Young’s moduli of the ZnO nanowires with the hexagonal structures are larger than those with the wurtzite structures at the same size. Within the nanowire size range considered, Young’s moduli of the ZnO nanowires decrease with increasing wire diameter. The electronic properties of these two types of ZnO nanowires exhibit distinctly different behaviors.