The optical absorption of nanowires with hexagonal cross-sections

Abstract

We study the optical absorption of semiconductor nanowires with hexagonal cross-sections, such as most wurtzite nanowires. The typical semiconductor nanowires have obvious quantum confinement in the cross-sections. We focus on the extent to which this kind of nanowires could be approximated as cylindrical ones. A numerical method is developed to calculate the optical absorption in such system. It is found that whether or not the approximation of the hexagonal cross-section as a circular one is valid depends on which energy levels are mainly considered. The analysis of the linear absorptions concludes that only those subbands corresponding to the energy levels in the cross sections having hexagonal symmetry can be optically excited to. The results are helpful for the optical applications of nanowires based on their fine energy structures.