Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 99: Gallium Nitride: Devices
HL 99.5: Vortrag
Freitag, 11. März 2016, 10:45–11:00, H17
Radiative recombination and parasitic luminescence in AlGaN-based UVC-LEDs — •Simon Kapanke1, Johannes Enslin1, Frank Mehnke1, Christian Kuhn1, Martin Guttmann1, Christoph Reich1, Ute Zeimer2, Tim Wernicke1, Markus Weyers2, and Michael Kneissl1,2 — 1Technische Universität Berlin, Institut für Festkörperphysik, Berlin — 2Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin
Ultraviolet (UV) light emitting diodes (LEDs) exhibit significant advantages compared to conventional UV light sources such as low power consumption and adjustable wavelength. Interesting applications for UVC-LEDs are compact gas sensing systems. However, achieving the required output power levels and high spectral purity is challenging. In this contribution, we present our recent investigations on the origin of parasitic luminescence observable in the electroluminescence measurements of AlGaN multiple quantum well LEDs emitting at 233 nm. The origin of the parasitic emission was located within the p-side of the LED heterostructure and analyzed by photoluminescence and cathodoluminescence measurements. Therefore, the Al-content in the p-side superlattice was varied resulting in a shift of the two main contributions of the parasitic luminescence towards shorter wavelength for higher Al-content. Additionally a reduced Mg-concentration in the p-side of the LEDs results in a reduced parasitic luminescence intensity indicating Mg-related deep level transitions to be involved as observed by Nakarmi et al. A detailed discussion of the experimental findings together with a comparison to recent literature will be provided.