Gallium nitride nanorod arrays as low-refractive-index transparent media in the entire visible spectral region.
Vertically aligned gallium nitride (GaN) nanorod arrays grown by the catalyst-free, self-organized method based on plasma-assisted molecular-beam epitaxy are shown to behave as subwavelength optical media with low effective refractive indices. In the reflection spectra measured in the entire visible spectral region, strong reflectivity modulations are observed for all nanorod arrays, which are attributed to the effects of Fabry-Pérot microcavities formed within the nanorod arrays by the optically flat air/nanorods and nanorods/substrate interfaces. By analyzing the reflectivity interference fringes, we can quantitatively determine the refractive indices of GaN nanorod arrays as functions of light wavelength. We also propose a model for understanding the optical properties of GaN nanorod arrays in the transparent region. Using this model, good numerical fitting can be achieved for the reflectivity spectra.
Department of Physics, National Tsing-Hua University, Hsinchu 300, Taiwan, Republic of China.
Hung-Ying
HY
Chen
Hon-Way
HW
Lin
Chen-Ying
CY
Wu
Wei-Chun
WC
Chen
Jyh-Shin
JS
Chen
Shangjr
S
Gwo
D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D005708:Gallium / Q000737:chemistry*; D007368:Interferometry / Q000295:instrumentation*; D008962:Models, Theoretical; D043942:Nanotubes / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods
C473348:gallium nitride; D005708:Gallium