Performance enhancement of AlGaN-based UV-LEDs inserted with a pin-doped AlGaN layer between the active region and electron-blocking layer

Suppression of efficiency droop in AlGaN based deep UV LEDs using double side graded electron blocking layer

“…However, different limiting factors [2] such as higher values of threading dislocation density, strong polarization effect, the junction heating effect, lower activated hole concentration and low light extraction efficiency result in significantly low (less than 20%) external quantum efficiency of AlGaN based DUV LEDs [3]. In order to overcome the above limitation, several approaches from the design perspective have been adopted to improve the internal quantum efficiency (IQE) and subsequent optoelectronics performance of these devices, for example, serrated p-AlGaN region [4], p-AlGaN/n-AlGaN/ p-AlGaN current spreading layer [5], step and superlattice hole reservoir layer [6], p-i-n junction last barrier structure [7], composition graded barrier [8] etc. As evident from the problems mentioned above and subsequent solutions approached by various research groups, different structural parameter optimization considerations play important roles in order to improve the performance of AlGaN based DUV LED's performance [9].…”