Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 27: GaN: Pr
äparation und Charakterisierung
HL 27.6: Vortrag
Mittwoch, 10. März 2004, 16:30–16:45, H15
Selforganized superlattice formation in AlGaN grown by MOVPE — •Andreas Able, Karl Engl, Josef Zweck, and Werner Wegscheider — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
Phase separation and demixing processes are well known phenomena in the system of group-III nitrides. Especially the clustering of indium in InGaN quantumwells is investigated thoroughly as it may be the key for lasing. In contrast to that, not much is yet known about large scale selforganization in the AlGaN ternary system. Few groups have reported formation of selforganized superlattices in this system, but no further studies were published1.
To clarify this process, we have grown a series of AlGaN structures on Si(111) by metal organic chemical vapor phase epitaxy (MOVPE). The samples were characterized using high resolution xray diffraction (HRXRD), high resolution transmission electron microscopy (HRTEM) as well as photoluminescence measurements.
The formation of superlattices with periods of about 3.1nm has been observed within a wide range of growth parameters. The results of these measurements are presented and a model for the underlying process is proposed.
1B. Neubauer, A. Rosenauer, D. Gerthsen, O. Ambacher and M. Stutzmann, Appl. Phys. Lett. 73, 930 (1998)