Current crowding and optical saturation effects in GaInN/GaN light-emitting diodes grown on insulating substrates

Current crowding in mesa-structure GaInN/GaN light emitting diodes (LEDs) g rown on insulating substrates is analyzed. A model developed reveals an exp onential decrease of the current density with distance from the mesa edge. Devices with stripe-shaped mesa geometry display current crowding and a sat uration of the optical output power at high injection currents. It is shown that the optical power saturation depends on the device geometry. It is al so shown that saturation is less pronounced in LEDs employing a ring-shaped mesa geometry, which reduces current crowding, as compared to the conventi onal square-shaped mesa geometry. (C) 2001 American Institute of Physics.