Stress-Induced Wurtzite to Hexagonal Phase Transformation in Zinc Oxide Nanowires

EK Lee and H Choi and YC Chung, JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, 11, 10595-10598 (2011).

DOI: 10.1166/jnn.2011.4063

The stress-induced wurtzite to hexagonal phase transformation in 01 (1) over bar0) oriented zinc oxide nanowires were investigated using a molecular dynamics simulation and reactive force field potentials. The yield strength of the 2.13 x 1.93 nm wurtzite nanowires is 12 GPa at 50 K. The wurtzite to hexagonal phase transformation was successfully observed at stress plateaus (5-5.5 GPa at 50 K) located after the yield point of the wurtzite phase. The wurtzite to hexagonal phase transformation was a result of the propagation of 0 (1) over bar 11 twinning boundaries. During the phase transformation, the wurtzite and hexagonal phases were clearly separated by the 0 (1) over bar 11 twinning boundaries. To analyze the difference between ceramic and metallic systems, all the calculation data of wurtzite to hexagonal transformation were compared with stress-induced phase transformation in metallic nanowires such as CuZr and NiAl. As the result of the 01 (1) over bar0 tensile loading of the ZnO nanowires, the hexagonal phase was obtained.