Publications

Enhanced light extraction in tunnel junction-enabled top emitting UV LEDs

Zhang, Yuewei; Allerman, A.A.; Krishnamoorthy, Sriram; Akyol, Fatih; Moseley, Michael; Armstrong, Andrew A.; Rajan, Siddharth

The efficiency of ultraviolet (UV) light-emitting diodes (LEDs) is critically limited by absorption losses in p-type and metal layers. In this work, surface-roughening-based light extraction structures were combined with tunneling-based top-layer contacts to achieve highly efficient top-side light extraction in UV LEDs. By using self-assembled Ni nanoclusters as an etch mask, the top surface-roughened LEDs were found to enhance the external quantum efficiency by over 40% for UV LEDs with a peak emission wavelength of 326 nm. The method described here can be used for fabricating highly efficient UV LEDs without the need for complex manufacturing techniques such as flip chip bonding.