Date of Award

Fall 2014

Degree Type


Degree Name

Master of Science in Mechanical Engineering (MSME)


Mechanical Engineering

First Advisor

Xiulin Ruan

Committee Chair

Xiulin Ruan

Committee Member 1

Jong H. Choi

Committee Member 2

Liang Pan


Semiconductor nanowires are attracting intense interest as a promising material for solar energy conversion for the new-generation photovoltaic (PV) technology. In particular, silicon core/multi-shell nanowires (SiNWs) are under active investigation for PV and solar water splitting applications because they offer novel approaches for solar to electric energy or fuel conversion leading to high efficiency devices. ^ Theoretical studies using the finite-different time-domain method have been performed to investigate the optical properties of many nanostructure arrays, however, they are computationally intensive and require periodic condition, which may not be satisfied with most fabricated samples. In the present study, effective medium approximation is performed to study the optical properties of vertically aligned Si core/multi-shell NW on Pt substrate in the wavelength range from 300 nm to 1000nm, which is of the most important interest to solar cells. The effective dielectric function of the Si core/multi-shell NWs layer is obtained from the Maxwell-Garnett approximation. Thin-film optics equations are employed to calculate the reflectance, transmittance, and absorptance of the Si core/multi-shell NWs at normal incidence. The effects of geometric parameters such as filling ratio and NW thickness are investigated to understand the light absorption and to facilitate the optimal design of high performance Si core/multi-shells NW solar cells.