Polarization of light emission by 460nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates

Measurements on the polarization of top- and side-emitted light as a function of direction are performed for 460nm GaInN unpackaged and packaged light-emitting diode (LED) chips with a multiquantum well (MQW) GaInN∕GaN active region grown on (0001) oriented sapphire substrates. Side emission is found to be highly polarized with the electric field in the plane of the MQW. Intensity ratios for in-plane to normal-to-plane polarization reach values as high as 7:1, while the total intensity for the in-plane polarization is more than twice as large compared to the normal-to-plane polarization. Despite these measured polarization characteristics, conventional packaged LEDs are found to be virtually unpolarized due to packaging.