Dresden 2014 – wissenschaftliches Programm
HL 19.4: Vortrag
Montag, 31. März 2014, 15:45–16:00, POT 151
Al(Ga)N electron blocking heterostructure design for high injection efficient 290 nm light emitting diodes — •Martin Guttmann1, Christoph Reich1, Tim Kolbe1,2, Frank Mehnke1, Christian Kuhn1, Jens Rass1,2, Tim Wernicke1, Mickael Lapeyrade2, Sven Einfeldt2, and Michael Kneissl1,2 — 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
We report on the optical and electronic properties of AlGaN-based light emitting diodes (LEDs) with a wavelength near 290 nm using different electron blocking heterostructures. Using a conventional Al0.7Ga0.3N:Mg electron blocking layer (EBL) carrier injection into 290 nm LEDs proves to be challenging. A broad parasitic luminescence around 350 nm was observed, originating from electron overflow into the Mg-doped Al0.4Ga0.6N/Al0.3Ga0.7N superlattice. Our studies show that by inserting an AlN:Mg interlayer (IL) between active region and EBL, electron overflow can be prevented. This is confirmed by electroluminescence measurements and simulations. With increasing IL thickness the emission output power increases, reaches a maximum at 3 nm and remains constant for thicker IL. We present a detailed analysis of the electron and hole injection into 290 nm LEDs using simulations as well as a study of current-voltage-characteristics and the emission spectra obtained from temperature dependent and pulsed electroluminescence measurements.