High Bandwidth GaN-Based Micro-LEDs at Temperatures up to 400  ∘ C

Gallium-nitride-based, blue micro-light-emitting diodes (micro-LEDs) with electro-optical −3 dB modulation bandwidths of 3.73 GHz at 11 kA/cm2 at room temperature and 4.00 GHz at 9 kA/cm2 at 200°C are reported. These bandwidths are the highest reported thus far for micro-LEDs. The micro-LEDs operate at high temperatures, up to 400°C, and bandwidths improve with increased temperatures. The lifetimes and recombination rates of the micro-LEDs active layer are determined by measuring and analyzing the impedance, modulation response, and radiative efficiency. This analysis shows increasing bandwidths with increasing current density and temperature resulting from dominant non-radiative lifetimes.