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HL: Halbleiterphysik

HL 50: Poster II

HL 50.22: Poster

Donnerstag, 30. März 2006, 16:30–19:00, P3

UHV-cathodoluminescence investigation of metastable light emission in GaN/GaInN quantum well structures — •Martina Finke, Daniel Fuhrmann, Carsten Netzel, Heiko Bremers, Uwe Rossow, and Andreas Hangleiter — TU Braunschweig, Inst. f. Angewandte Physik, 38106 Braunschweig

In GaN/GaInN quantum well structures, the spontaneous and the piezoelectrical fields have a strong effect on the optical properties. The spontaneous field is normally shielded by charged species on the surface. Since the spontaneous field counteracts the piezoelectrical field, a blueshift in the peak-position of the luminescence and an increased intensity is expected by a removal of the deposited particles. We investigated the cathodoluminescence for various surface conditions after etching, annealing and electron beam exposition in an UHV environment. We studied several GaInN quantum well structures with different indium concentration and layer thicknesses at room and low temperatures. From time dependent measurements we find that the intensity of the luminescence of QW samples first increases rapidly and then decreases at longer times during electron beam exposure. We attribute this to a change of the spontaneous field due to electron-stimulated-desorption or due to a stimulated chemical reaction induced by the electron beam. Using systematic experiments we try to understand how the surface conditions influence the luminescence properties of QW structures via the effect of the spontaneous polarisation.