GHz bandwidth GaAs light-emitting diodes

Double-heterostructure GaAs/GaAlAs light-emitting diodes ~LEDs! have been fabricated with the emitter regions beryllium doped to 2310 and 7310 cm. The 7310 cm doped emitters have an internal quantum efficiency of 10% and an optical modulation bandwidth of 1.7 GHz. The steady-state optical output power versus the input current shows an external efficiency of 2.5 mW/mA. The 2310 cm emitters have internal quantum efficiencies as high as 80%, but a reduced cutoff frequency. The external quantum efficiency reaches 10 mW/mA. These high-speed LEDs are produced by reducing the radiative lifetime to 100–250 ps without significantly degrading internal quantum efficiency. The current results on heavily beryllium-doped LEDs exhibit, to the best of our knowledge, the highest external efficiencies to date for such high doping and efficiencies close to that observed for lower-doped LEDs. © 1999 American Institute of Physics. @S0003-6951~99!03621-9# APPLIED PHYSICS LETTERS VOLUME 74, NUMBER 21 24 MAY 1999