Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 41: GaN: preparation and characterization II

HL 41.3: Vortrag

Donnerstag, 26. März 2009, 10:00–10:15, BEY 154

Control of MOVPE InGaN quantum dot density and emission wavelength and applications in light emitting structures — •Christian Tessarek, Timo Aschenbrenner, Stephan Figge, Joachim Kalden, Kathrin Sebald, Jürgen Gutowski, and Detlef Hommel — Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen

InGaN quantum dots (QDs) are very promising for the application in laser structures emitting in the blue to green spectral region due to the expected lower threshold currents in comparison to a quantum well (QW) based device.

Our approach to form capped InGaN QDs is a two-step growth method [1] which is composed of an InGaN nucleation layer (NL) followed by an (In)GaN protection layer. There are indications that spinodal decomposition is the driving force for the transition of the NL into self-assembled QDs.

We will show how the emission wavelength can be tuned from 440 nm to 520 nm by varying the NL thickness and the In content in the protection layer. Atomic force microscope and photoluminescence (PL) results reveal a QD density dependence on the NL growth temperature.

The strong room temperature PL emission intensity of the QDs promises an improvement in device performance compared to QW based devices. We will demonstrate the successful implementation of these InGaN QDs into light emitting diodes and laser structures.

[1] T. Yamaguchi et al., phys. stat. sol. (c) 4, No. 7, 2407-2410 (2007)