High polarization and fast modulation speed of dual wavelengths electroluminescence from semipolar (20-21) micro light-emitting diodes with indium tin oxide surface grating
Haojun Zhang, Panpan Li, Hongjian Li, Jie Song, Shuji Nakamura, Steven P. DenBaars
Abstract
We present highly polarized dual wavelength semipolar InGaN micro-light-emitting diodes (μLEDs) by combining an indium tin oxide (ITO) surface grating and Al-coated dual-color surface plasmons (DSPs). The ITO grating DSPs enable a significant enhancement of the polarization ratio (PR) from electrically driven semipolar (20-21) μLEDs with dual emission wavelengths: the overall PR was increased by 1.7-folds and the output power was enhanced by 78% as compared to the conventional semipolar μLEDs at an injection current density of 100 A/cm2. Moreover, a high 3 dB modulation bandwidth of 612 MHz is achieved at ∼1.4 kA/cm2 in a visible-light communication (VLC) system, suggesting a near 1.24 Gbit/s under a non-return-to-zero on-off keying modulation scheme. This design marks significant progress in developing polarized μLEDs with potential applications in various fields, such as displays and VLC.