Vertical-surface-emitting diode using a GaN buried tunnel junction current aperture

We have been demonstrated vertical-surface-emitting InGaN/GaN blue-light-emitting diodes using a GaN buried tunnel junction (TJ) current aperture for a lateral current confinement. The current confinement aperture for lateral injection current was defined by mesa-etch of a TJ structure and regrowth of a current-blocking layer surrounding the TJ mesa. The surface optical quality of the regrowth region grown on the TJ mesa was quite smooth, and the value of the root-mean-square surface roughness had little effect on the performance of the device. A lateral electron current drove the tunnel contact junction, providing hole injection into the active region. The very uniform light emission through a buried TJ aperture shows that the buried TJ structure acts very effectively as a confinement aperture for lateral current injection, particularly in GaN-based vertical-cavity surface-emitting lasers.