Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 52: Nitrides: Devices
HL 52.2: Vortrag
Freitag, 22. März 2024, 09:45–10:00, EW 015
Hole transport in AlGaN-based far-UVC LEDs with multiple quantum wells — •Franz Biebler1, Marcel Schilling1, Jakob Höpfner1, Massimo Grigoletto2, Tim Wernicke1, and Michael Kneissl1 — 1Technische Universität Berlin, Institute of Solid State Physics, Hardenbergstraße 36, 10623 Berlin, Germany — 2Ferdinand-Braun-Institut gGmbH, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
Understanding the hole transport in AlGaN-based far-UVC LEDs with wavelengths below 240 nm is crucial for improving the efficiency of these devices. In order to obtain an insight into this topic far-UVC LEDs with mixed wavelength AlGaN multiple quantum wells (MQW) were grown by metal organic vapor phase epitaxy (MOVPE), consisting of multiple QWs emitting at 233 nm and a single QW emitting at 250 nm. When the 250 nm wavelength QW is grown close to the n-side, it acts as an indicator for the presence of holes. In addition, the number of 233 nm QWs was varied between two and twenty. Temperature dependend electroluminescence-measurements have been performed on all samples. Analysis of the spectra shows a decrease in 250 nm intensity with increasing number of 233 nm QWs, due to capturing and confinement of the holes by 233 nm QWs. Comparing pulsed with continuous wave measurements for different current densities shows a significant decrease of intensity due to heating for the short wavelength QWs. Cooling of the LEDs down to 100 K reduces mobility of holes, which leads to a increase of the power ratio of 233 nm radiation to 250 nm radiation.