Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 85: Poster Session II

HL 85.116: Poster

Donnerstag, 17. März 2011, 18:00–21:00, P4

Properties of quaternary (Al, Ga, In)N layers and MQWs — •Lars Groh, Christoph Hums, Armin Dadgar, Jürgen Bläsing, and Alois Krost — Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg

The achievement of efficient green LEDs is at present mostly prohibited by the Quantum Confined Stark-Effect (QCSE), which leads to a low quantum efficiency for longer wavelengths. Responsible for the QCSE are strong polarization fields in growth direction of c-axis oriented group-III-nitride heterostructures, especially within the quantum wells. To reduce or eliminate these polarization fields, mainly two approaches are followed. The first and most popular one is to change the growth direction to semi- or non-polar facets. Our approach is to change the barrier material in order to control the band gap and in particular the polarization field strength. By this the polarization of well and barrier can be nearly matched, with the benefit of the well established growth in c-axis direction which is, e. g., low in stacking fault density. We have grown by MOVPE GaInN/AlGaInN MQWs on silicon and sapphire substrates to investigate the effect of different growth conditions on the composition and luminescence of these structures. PL, (HR)XRD and FE-SEM measurements have been performed. The results from these measurements are compared to the predictions from theory.