Status and Prospects of AlN Templates on Sapphire for Ultraviolet Light‐Emitting Diodes
Sylvia Hagedorn, Sebastian Walde, A. Knauer, Norman Susilo, Daniel Pacak, Leonardo Cancellara, Carsten Netzel, Anna Mogilatenko, C. Hartmann, Tim Wernicke, Michael Kneissl, M. Weyers
Abstract
Herein, the scope is to provide an overview on the current status of AlN/sapphire templates for ultraviolet B (UVB) and ultraviolet C (UVC) light‐emitting diodes (LEDs) with focus on the work done previously. Furthermore, approaches to improve the properties of such AlN/sapphire templates by the combination of high‐temperature annealing (HTA) and patterned AlN/sapphire interfaces are discussed. While the beneficial effect of HTA is demonstrated for UVC LEDs, the growth of relaxed AlGaN buffer layers on HTA AlN is a challenge. To achieve relaxed AlGaN with a low dislocation density, the applicability of HTA for AlGaN is investigated.