Critical aspects of deep-UV LED design and operation

Efficiency of AlGaN deep-UV LEDs is considerably lower than that of InGaN/GaN based blue and green light emitters because of (i) a lower internal quantum efficiency controlled by threading dislocation density, (ii) strong absorption of UV light by metallic contacts and conventionally used p-GaN contact layer, and (iii) a lower electrical efficiency and enhanced LED self-heating originated from poor conductivity of AlGaN cladding layers and high AlGaN/metal Ohmic contact resistance. Coupled electrical, thermal and optical simulations allow identifying the critical factors limiting the deep-UV LED efficiency and suggesting ways to improve the device performance. In this work, we consider various approaches to optimization of deep-UV LEDs.