2020, Hagedorn, Sylvia, Walde, Sebastian, Knauer, Arne, Susilo, Norman, Pacak, Daniel, Cancellara, Leonardo, Netzel, Carsten, Mogilatenko, Anna, Hartmann, Carsten, Wernicke, Tim, Kneissl, Michael, Weyers, Markus

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. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim