Whispering gallery mode in periodic InGaN-based hexagonal nanoring arrays grown by rf-MBE using Ti-mask selective-area growth

We fabricated periodic IncaN-based hexagonal nanoring arrays by rf-molecular beam epitaxy (rf-MBB) with Ti-mask selective area growth (SAG). Multiple photoluminescence peaks from InGaN-based hexagonal nanorings were observed in room temperature photoluminescence (RT-PL) measurements with 325 nm He-co laser. We employed a simple plane wave model and a two-dimensional finite difference time domain (2D-FDTD) method in the numerical analysis to investigate these multiple pearks. Experimental data was in good coincidence with calculated data, evincing that whispering gallery modes (WGMS) supported in the InGaN-based hexagonal nanorings were responsible for the multipeaks.