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HL: Fachverband Halbleiterphysik

HL 9: Poster 1

HL 9.29: Poster

Montag, 23. März 2009, 14:30–17:00, P2

Microscopic properties of spontaneously formed non-polar and semi-polar GaN growth domains on r-plane sapphire — •B. Bastek, J. Christen, T. Hempel, P. Veit, M. Wieneke, A. Dadgar, J. Bläsing, and A. Krost — Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Germany

We present a study about the microscopic optical and structural properties of spontaneously developed growth domains of non-polar GaN and semi-polar GaN on the same sapphire wafer. For optimizing the lattice match between a-plane GaN and r-plane Sapphire the growth conditions for an AlInN nucleation layer were investigated. Most of the samples exhibit layers with pure a-plane GaN of good crystallographic quality. However, on some samples a circular region of semi-polar (nearly (11-26)) GaN emerged. The thickness of the frame strongly depends on the chosen growth conditions for the nucleation layer. At the boundary the optical properties of the two growth domains drastically change. In the non-polar a-plane GaN domains the basal plane stacking fault (BSF) luminescence exceeds the excitonic luminescence by a factor of three which is specific for hetero-epitaxial non-polar GaN. In contrast the excitonic luminescence dominates the BSF emission by a factor of seven in the semi-polar region accompanied by an absolute increase of the intensity. Besides structural properties we will show *-Cathodoluminescence and TEM images of the boundary region.