Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 29: III-V Semiconductors I (mainly Nitrides)

HL 29.7: Vortrag

Dienstag, 27. März 2012, 11:15–11:30, EW 201

MOVPE growth of semi-polar GaN LED structures on planar Si(112) and Si(113) substrates — •Roghaiyeh Ravash, Armin Dadgar, Anja Dempewolf, Peter Veit, Thomas Hempel, Jürgen Bläsing, Jürgen Christen, and Alois Krost — Otto-von-Guericke-Universität Magdeburg, Institut für Experimentelle Physik, Fakultät für Naturwissenschaften,Universitätsplatz 2, 39106 Magdeburg, Germany

We present semi-polar GaN LED structures grown on non-patterned Si(112) and Si(113) substrates by MOVPE to improve light emitter efficiency. The samples were investigated by X-ray diffraction measurements, photoluminescence (PL), cathodoluminescence (CL) as well as field emission scanning electron microscopy (FE-SEM). In samples, which were simultaneously grown on Si(112) and Si(113), we observed that structures on Si(112) consist of a relatively smooth surface but those on Si(113) have a V-pit dominated surface with a three dimensional growth mode of the GaN layers resulting in a rough GaN surface. The low temperature CL spectra of the sample grown on Si(112) exhibit a dominant InGaN/GaN MQWs emission. But CL spectra of the MQWs grown on Si(113) show two peaks related to the rough surface resulting in inhomogeneous indium incorporation and / or thickness fluctuations in the MQWs. For an optimized sample grown on Si(113), the surface undulation of a first GaN layer is strongly reduced obtaining a LT-AlN interlayer nearly parallel to the substrate surface. There, CL measurements show only one dominant MQWs emission.