Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 39: Poster III

HL 39.1: Poster

Wednesday, March 19, 2025, 15:00–18:00, P3

Termperature dependent electroluminescence spectroscopy of far-UVC-LEDs with varying AlGaN quantum well thickness — •Max Dittmer¹, Jakob Höpfner¹, Markus Blonski¹, Tim Kolbe², Sylvia Hagedorn², Hyun Kyong Cho², Jens Rass², Sven Einfeldt², Tim Wernicke¹, Markus Weyers², and Michael Kneissl¹ — ¹TU Berlin, Insitute of Solid State Physics, Berlin, Germany — ²Ferdinand-Braun-Insitut (FBH), Berlin Germany

AlGaN far-UVC-LEDs with emission wavelengths below 240 nm require AlGaN layers with such high aluminium molefractions that p-doping with magnesium is inefficient due to its high ionization energy. An alternative method of p-doping is distributed polarization doping (DPD), which induces charge carriers by polarization charges. We will present the results of temperature dependent electroluminescence spectrocopy on 233 nm AlGaN LEDs with DPD gradient, grown by metal organic vapor phase epitaxy (MOVPE). We investigated the impact of the quantum well (QW) width from 1.3 nm to 7.6 nm. Most importantly we found the 2.6 nm LED to be the most efficient at room temperature. The LEDs exhibit an S-shape in the emission energy in dependence of the temperature and the highest internal quantum efficiency of 55%, was measured at 200 K.

Keywords: UVC LEDs; Electroluminescence; Temperature dependence; Quantum well thickness variation; Aluminum Gallium Nitride