Polarized emission characteristics of UV-LED with subwavelength grating

We investigated polarized emission from a GaN-based ultraviolet light-emitting diode (UV-LED) with a subwavelength grating (SWG) on the surface. The electroluminescence (EL) spectra showed that the UV-LED exhibits high polarization selectivity, as high as s-polarization: p-polarization = 4 : 1 at a wavelength of 360 nm. The polarized EL characteristics were discussed by the theoretical consideration of Bloch modes resulting from the spatial periodicity of the refractive index in the SWG region and also by finite difference time domain calculations to explore the electromagnetic field. We succeeded in demonstrating the feasibility of a highly polarized UV-LED grown on c-plane sapphire.

© 2014 The Japan Society of Applied Physics