Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 10: Nitrides
HL 10.6: Vortrag
Montag, 5. September 2022, 16:15–16:30, H34
Realizing tunnel junctions in AlGaN-based UVC light emitting diodes emitting at 232 nm — •Verena Montag1, Frank Mehnke1, Martin Guttmann2, Luca Sulmoni1, Christian Kuhn1, Johannes Glaab2, Tim Wernicke1, Markus Weyers2, and Michael Kneissl1,2 — 1Technische Universität Berlin, Institute of Solid State Physics, Hardenbergstraße 36, 10623 Berlin, Germany — 2Ferdinand-Braun-Institut, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
An ultraviolet C (UVC) -transparent p-AlGaN layer is needed to overcome the strong absorption of p-layers in deep UV light emitting diodes (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). This allows for low resistivity n-layers and n-contacts on both sides of the device. We have successfully demonstrated fully transparent AlGaN-based TJ-LEDs emitting at 232 nm grown entirely by metal-organic vapor phase epitaxy. A thin GaN interlayer was implemented to enhance carrier tunneling at the TJ interface. Typically, the operating 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, 77 µW and 0.29%, respectively, measured on wafer at 5 mA in cw operation. This is the first reported TJ-LED in the wavelength range below 240 nm.