Second-order scattering induced reflection divergence and nonlinear depolarization on randomly corrugated semiconductor nano-pillars
Journal
Progress in Electromagnetics Research
Journal Volume
117
Pages
67-81
Date Issued
2011
Author(s)
Abstract
Second-order scattering induced reflection divergence and nonlinear depolarization on randomly sub-wavelength corrugated semiconductor nano-pillar surface is observed, which explains the nonlinear transverse electric (TE)/transverse magnetic (TM) mode transformation of the nano-pillar surface reflection with diminishing Brewster angle. The reflected field polarization ratios are increased from 0.12 to 0.65 and from 0.11 to 0.55 under TE- and TM- mode incidences by increasing Si nano-pillar height from 30 to 240 nm. A small-perturbation modeling corroborates the scattering induced second-order polarization transformation to depolarize the reflection from highly corrugated Si nano-pillar surface. The higherfield polarization ratio at TE-mode reflection caused by a severer inhomogeneous Si nano-pillars oriented in parallel with surface normal is concluded. With the enlargedfield polarization ratio under TM- mode incidence, the angular dependent reflectance spectra with a gradually diminished and shifted Brewster angle from 74° to 45° can be simulated. The nano-roughened surface induced second-order scattering model correlates the diminishing Brewster angle with the surface depolarized reflection.
SDGs
Type
journal article