Well width study of InGaN multiple quantum wells for blue-green emitter

V. Hoffmann^a, C. Netzel^a, U. Zeimer^a, A. Knauer^a, S. Einfeldt^a, F. Bertram^c, J. Christen^c, M. Weyers^a, G. Tränkle^a, M. Kneissl^a,b

^a Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
^b Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
^c Institut für Experimentalphysik, Otto-von-Guericke-Universität Magdeburg, 39106 Magdeburg, Germany

Published in:
J. Cryst. Growth, vol. 312, no. 23, pp. 3428-3433 (2010).
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Abstract:
InGaN/GaN multiple quantum well structures emitting in the blue/green wavelength region were grown by metal organic vapor phase epitaxy. By reducing the quantum well growth time the influence of the quantum well thicknesses between 3.8 and 1.1 nm on the indium incorporation and the distribution of indium in the quantum wells in growth direction were investigated. X-ray diffraction measurements show that the average indium mole fraction in the quantum wells decreases with reducing quantum well width due to a delay in the indium incorporation at the barrier/well interface. Quantitative analysis reveals a segregation length of about 2 nm as a measure of the graded region in growth direction.Cathodoluminescenceimagingrevealsthatthespatialvariationofthewavelengthis reduced with decreasing quantum well thickness down to 1.7 nm. Reducing the width of the quantum well further results in an increase of the spatial wavelength variation.

Keywords:
A1. Segregation A1. High resolution X-ray diffraction A3. Low press A3. Metal organic vapor phase epitaxy B1. Nitrides B2. Semiconducting indium compounds

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