(296g) Phase-Field Modeling of Spiral Steps and Island Nucleation During the Growth of Crystalline ZnO Nanowires

Yeckel, A., University of Minnesota
Derby, J. J., University of Minnesota
Wang, W., University of Minnesota

Arrays of crystalline zinc oxide (ZnO) nanowires are grown from supersaturated liquid phases and are of particular interest for the fabrication of nanowire-based, dye sensitized solar cells (DSSCs). These low-cost, photovoltaic devices are especially attractive due to their potential for very low cost and reasonably high efficiency. The quality and microstructure of the ZnO nanowire array determines the solar cell's performance, yet a quantitative understanding of the effects of key process-level variables on the growth of these structures is lacking. This work addresses fundamental scientific issues on the crystal growth mechanisms that dominate the growth of ZnO nanowires.

We develop a fundamental theoretical model based on the phase-field approach to simulate nano-scale island growth and spiral step growth on crystal surfaces in a supersaturated liquid. Results obtained by this work will help understanding how experimental factors affect the crystal growth and crystal microstructures, the correlation between island growth and spiral growth, and how these two mechanisms transform under certain growth conditions.