Abstract
Light-emitting diode (LED) is one of the most important light sources due to its low power consumption and long lifetime. In this letter, we present the high-frequency characteristics of GaN-based green LEDs with different aperture diameters. In order to get higher current density, we use ring-shaped electrode to confine the current injection. Unlike conventional LEDs, we only use its natural feature to get a high modulation bandwidth. The LEDs investigated have a peak emission wavelength of 500 nm. The highest optical 3-dB modulation bandwidth is ∼ 463 MHz at 50 mA for the 500-nm green GaN-based LED with an aperture diameter of 75 μ m. It is the highest bandwidth yet reported for the green GaN-based LEDs. The LED also exhibits a relatively high output power of ∼ 1.6} mW at 50 mA as compared with other high-speed LEDs. Such the LEDs can be applied to plastic optical fiber and visible light communication in the future. © 2014 IEEE.