Open AccessAbnormal polarization switching phenomenon in a-plane AlxGa_1-xN
Author(s) -
Huei Min Huang,
Hung Hsun Huang,
YuhRenn Wu,
TienChang Lu
Publication year - 2010
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.021743
Subject(s) - polarization (electrochemistry) , optics , photoluminescence , polarization rotator , degree of polarization , physics , materials science , atomic physics , scattering , chemistry , birefringence
The optical polarization properties of a-plane AlxGa(1-)xN films have been investigated by polarization-dependent photoluminescence (PL). The degree of polarization decreased with increasing the Al composition, and the main optical polarization direction switched from ε ⊥ cto ε // c at about x = 0.07 due to the valence band switching, representing that the optical transition energy of ε // c is surpassing that of ε ⊥ c. However, with the Al composition larger than x = 0.1, the higher energy optical transitions of ε // cexhibited the stronger PL intensity, opposite to the normal situations that higher energy states commonly have weaker PL intensity than the lower energy states. We utilized the 6 × 6 k.p model and the lambertian-like radiation pattern assumption to explain this abnormal optical polarization switching behavior in the a-plane AlxGa(1-)xN layers and obtained good agreement with the experimental results.