Learn More
Selective-area epitaxy is used to form three-dimensional (3D) GaN structures providing semipolar crystal facets. On full 2-in. sapphire wafers we demonstrate the realization of excellent semipolar material quality by introducing inverse GaN pyramids. When depositing InGaN quantum wells on such a surface, the specific geometry influences thickness and(More)
Small-signal analysis and polarization stability performance of single-mode VCSELs for MEMS atomic clock applications " , in Proc. [3] A. Gadallah and R. Michalzik, " Densely-packed 2-D matrix-addressable vertical-cavity surface-emitting laser arrays " , in Proc. High-power single-higher-order-mode VCSELs for optical particle manipulation " , in(More)
We report on the development of a diamond-on-sapphire microelectrode quadrupole array, substituting the commonly used inert metal electrode material by nano-crystalline diamond (NCD). This allows to combine the transparency (desired for fluorescence analysis) with the properties of an inert quasi-metallically doped diamond electrode. The NCD film was(More)
Group III nitrides are promising materials for light emitting diodes (LEDs). The occurrence of structural defects strongly affects the efficiency of these LEDs. We investigate the optical properties of basal plane stacking faults (BFSs), and the assignment of specific spectral features to distinct defect types by direct correlation of localized emission(More)
Ga x In 1−x N quantum wells grown by metal organic vapor phase epitaxy on a plane GaN grown on r plane sapphire substrate typically show relatively large surface pits. We show by correlation of low temperature photoluminescence, cathodoluminescence, scanning and transmission electron microscopy that the different semipolar side facets of these pits dominate(More)
Cathodoluminescence spectra recorded with high spatial and wavelength resolution on tilted ZnO epitaxial layers allow to identify a very prominent emission peak at 3.314 eV as a free electron to shallow acceptor (E A % 130 meV) transition. By correlation with TEM cross-section images recorded on the same samples we can find these acceptor states to be(More)
  • 1