Regensburg 2007 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 46: Poster 2
HL 46.15: Poster
Thursday, March 29, 2007, 15:00–17:30, Poster A
Analysis of the Current-Voltage Characteristics and Electroluminescense of GaN-based Light Emitting Diodes — •T. Kolbe1, J.-R. v. Look1, M. Kneissl1,2, A. Knauer2, V. Hoffmann2, S. Einfeldt2, and M. Weyers2 — 1TU Berlin, Institute of Solid State Physics, Hardenbergstr. 36, 10623 Berlin, Germany — 2Ferdindand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
Light Emitting Diodes (LEDs) based on III-nitride semiconductors have attracted great interest in recent years. One of the key challenges in making high brightness blue-violet LEDs is efficient current injection into the active regions of GaN-based p-n junctions. Carrier confinement, series resistance of the p-doped layers, as well as ohmic metal contacts, are particularly problematic in these materials. In this work we present an analysis of the current-voltage characteristics and electroluminescense (EL) of different GaN-based heterostructures in order to optimize current-injection and LED efficiencies. The devices in our investigation were grown by MOVPE on (0001) sapphire substrates. EL measurements are carried out to determine electrical and optical properties which are used as a feedback for the optimisation of the epitaxial growth process. By measuring the forward and reverse bias current-voltage characteristics, leakage currents, diode series resistance and ideality factors can be determined. This allows us to explore the correlation between these parameters and the heterostructure design, e.g. GaN pn-homojunctions and InGaN multiple quantum well (MQW) heterostructures with and without a p-AlGaN electron blocking layers.