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HL: Fachverband Halbleiterphysik
HL 25: Poster: Nitrides
HL 25.9: Poster
Montag, 20. März 2017, 15:00–19:00, P2-OG2
Influence of p-AlGaN superlattice and quantum barrier composition on electro-optical characteristics of UVC-LEDs — •Pascal Röder1, Christian Kuhn1, Sylvia Hagedorn2, Arne Knauer2, Tim Wernicke1, Markus Weyers2, and Michael Kneissl1 — 1Technische Universität Berlin, Institute of Solid State Physics — 2Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin
Ultraviolet light emitters can be used for the disinfection of water, sterilizing surfaces, and detecting gases such as NOx and SO2. However, the external quantum efficiency (EQE) of AlGaN-based LEDs in the UVC wavelength range (200 nm to 280 nm) is still relatively low. In this paper, we investigate the effect of carrier confinement on the EQE of UVC-LEDs emitting near 270 nm.
Electron leakage into the p-side of UVC-LEDs is a major contributor to the low efficiency. In order to investigate the carrier confinement we varied the aluminum content of the quantum barriers and the Mg-doped AlGaN short period superlattice (p-SPSL). The results indicate an intricate interplay of the band offsets of all interfaces. This includes the confinement of electrons in the quantum wells and the electron leakage from the last barrier into p-SPSL.
By improving the carrier confinement UVC-LEDs emitting at 270 nm with an output power of 0.9 mW at 20 mA (EQE 0.95 %, measured on wafer) have been fabricated.