Pyramidal GaN structures were deposited by selective metal-organic vapor phase epitaxy (MOVPE) to create semipolar facets. On top of these pyramids InGaN was deposited forming nanostructures of different dimensionality according to the varying strain regions along the pyramid.
We have studied the emission properties of pyramid ensembles using low-temperature time-resolved photoluminescence (PL) spectroscopy. The observed PL spectra in conjunction with the revealed decay times indicate already the expectations of regions with different confinement on the pyramids. Changing the size of the pyramids and the indium supply lead to variations in the emission wavelength of the ensemble.
Spatially resolved cathodoluminescence (CL) experiments were performed to analyze locally the emission properties all over the pyramidal structures. We have found that indeed the indium accumulates at the edges and the apex of the pyramids. Furthermore the emission of the quantum well (QW) sidewalls exhibit also a shift in emission energy which can be attributed again to a change of the In-content or a change of the QW thickness.