Enhanced Emission from a Light-Emitting Diode Modified by a Photonic Crystal

Enhanced light output is observed from a light-emitting diode (LED) structure containing a two-dimensional (2D) photonic crystal. The capture of emitted light into planar waveguide modes reduces the extraction efficiency of LEDs. Here, 2D photonic crystals are utilized to: 1) enhance the extraction of light in the vertical direction from an LED and 2) enhance optical pumping by directly coupling light from a pump laser into the LED structure. Spatially and spectrally-resolved photoluminescence (PL) is used to characterize the enhancements. A 100-fold enhancement in extraction for a single wavelength into the vertical direction is obtained without the photonic crystal penetrating the active material.