Dresden 2020 – wissenschaftliches Programm
Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 8: Nitrides: Devices
HL 8.2: Vortrag
Montag, 16. März 2020, 09:45–10:00, POT 51
Realizing tunnel junctions in MOVPE-grown AlGaN-based UVC LEDs emitting at 233 nm — •Verena Montag1, Luca Sulmoni1, Frank Mehnke1, Martin Guttmann1, Christian Kuhn1, Norman Susilo1, Johannes Glaab2, Tim Wernicke1, Markus Weyers2, and Michael Kneissl1,2 — 1Technische Universität Berlin, Institute of Solid State Physics — 2Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin
A highly conductive and UV-transparent p-AlGaN layer is needed to overcome the strong absorption and the poor current spreading of p-contacts in deep UV LEDs. However, transparent p-AlGaN layers exhibit high sheet and contact resistances resulting in very large operating voltages. A promising alternative to standard p-contacts is the injection of holes into the AlGaN quantum well by tunnel heterojunctions (TJs) allowing for low resistivity n-layers and n-contacts on both sides of the device. This way, a transparent top n-AlGaN layer can be used as an excellent current spreading layer together with a metal reflector enhancing the light extraction. We have successfully demonstrated fully transparent AlGaN-based TJ-LEDs emitting at 233 nm grown entirely by MOVPE. A thin GaN interlayer was implemented to enhance carrier tunneling at the TJ interface. Typically, the operation voltages, the output powers and the external quantum efficiencies of a 0.15 mm2 TJ-LED featuring a 8 nm thick GaN interlayer are 24 V, 83 µW and 0.16%, respectively, measured on wafer at 10 mA in cw operation.