Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 53: GaN: Devices

HL 53.6: Vortrag

Mittwoch, 13. März 2013, 11:15–11:30, H15

Comparison of different carrier injection mechanisms in 290 nm LEDs — •C. Kuhn¹, F. Mehnke¹, T. Wernicke¹, J. Stellmach¹, T. Kolbe¹, C. Reich¹, M. Guttmann¹, V. Kueller², A. Knauer², M. Weyers², and M. Kneissl^1,2 — ¹Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany — ²Ferdinand Braun Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany

To achieve high external quantum efficiency in UV-B LEDs a high injection efficiency for electrons and holes is necessary. The injection efficiency is reduced by electron leakage into the p-doped side of the LED. Previous examinations of LEDs with varied emission wavelength between 285 nm and 345 nm, including an Al_0.7Ga_0.3N:Mg electron blocking layer have shown a strong p-side luminescence which is dominating the emission especially at shorter wavelengths. To overcome this problem of electron leakage an additional interlayer consisting of undoped AlN or Al_xGa_1−xN (x>0.8) was introduced. This interlayer blocks electrons while allowing a hole current to the active region by tunneling. Electroluminescence spectra of 290 nm LEDs grown by MOVPE with AlN interlayers with a thickness from zero to 6 nm show reduced p-side luminescence due to reduced electron leakage. The optimal interlayer thickness was found to be 4 nm which is consistent with simulations. For thicker interlayers the hole injection is reduced. Further investigations of the influence of a varied aluminum content of an AlGaN interlayer will be presented.