Investigation of Enhanced Light Absorption in GaN Nanorod Arrays by Finite-Difference Time-Domain Method

Finite-difference time-domain simulation of GaN nanorod arrays with linearly polarized ultraviolet (UV) (325 nm) and visible (513 nm) light has been carried out.Enhanced light absorption of nanorods with confined electric field in the surrounding gap was observed.To identify the rationale of this finding, we studied their three-dimensional graphical profile and then realized that 1) modal resonance is developed with absorption gain in the UV region and 2) reflection at the interface with substrate leads to a subtle increase of absorption of visible light.By solving the eigenvalue equation, we also confirmed that TM 11 mode of leaky-mode resonance is responsible for the observed modal absorption of UV light.