MOVPE-grown AlGaN-based tunnel heterojunctions enabling fully transparent UVC LEDs

作     者：Christian Kuhn Luca Sulmoni Martin Guttmann Johannes Glaab Norman Susilo Tim Wernicke Markus Weyers Michael Kneissl 

作者机构：Technische Universitat Berlin Institute of Solid State Physics Hardenbergstr. 36 EW6-1 10623 Berlin Germany Ferdinand-Braun-Institut Leibniz-Institut fur Hochstfrequenztechnik Gustav-Kirchhoff-Str. 4 12489 Berlin Germany 

出 版 物：《Photonics Research》 (光子学研究（英文版）)

年 卷 期：2019年第7卷第5期

页      面：I0008-I0012页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：Bundesministerium für Bildung und Forschung(BMBF)“Advanced UV for Life” Project(03ZZ0134C) Deutsche Forschungsgemeinschaft(DFG)Collaborative Research Centre “Semiconductor Nanophotonics”(CRC787 9315) 

主　　题：MOVPE-grown AlGaN-based UVC LEDs 

摘      要：We report on AlGaN-based tunnel heterojunctions grown by metalorganic vapor phase epitaxy enabling fully transparent UVC LEDs by eliminating the absorbing p-AlGaN and p-GaN layers. Furthermore, the electrical characteristics can be improved by exploiting the higher conductivity of n-AlGaN layers as well as a lower resistance of n-contacts. UVC LEDs with AlGaN:Mg/AlGaN:Si tunnel junctions exhibiting single peak emission at268 nm have been realized, demonstrating effective carrier injection into the AlGaN multiple quantum well active region. The incorporation of a low band gap interlayer enables effective tunneling and strong voltage ***, the interlayer thickness is systematically varied. Tunnel heterojunction LEDs with an 8 nm thick GaN interlayer exhibit continuous-wave emission powers 3 m W near thermal rollover. External quantum efficiencies of 1.4% at a DC current of 5 m A and operating voltages of 20 V are measured on-wafer. Laterally homogeneous emission is demonstrated by UV-sensitive electroluminescence microscopy images. The complete UVC LED heterostructure is grown in a single epitaxy process including in situ activation of the magnesium acceptors.