The high speed on-off performance of GaN-based light-emitting diodes (LEDs) grown in c-plane direction is limited by long carrier lifetimes caused by spontaneous and piezoelectric polarization. This work demonstrates that this limitation can be overcome by m-planar core-shell InGaN/GaN nanowire LEDs grown on Si(111). Time-resolved electroluminescence studies exhibit 90-10% rise- and fall-times of about 220 ps under GHz electrical excitation. The data underline the potential of these devices for optical data communication in polymer fibers and free space.

The recombination dynamics of vapor-liquid-solid grown GaAs-nanowires with an axial p-n heterojunction is investigated by spatially and time-resolved photoluminescence spectroscopy. By scanning across the doping transition of single p-n and n-p doped nanowires, respectively, the particular influence of surface losses in differently doped areas is studied. We found a significantly reduced non-radiative recombination for the n-doped region compared to the p-doped one, which can be attributed to suppressed surface losses because of the characteristic band bending at the surface.

Crystalline Ga 2 O 3 nanowires are synthesized via an Au-catalyzed, as well as a self-catalyzed, growth by a low-temperature metal-organic (MO)CVD process using t Bu 3 Ga as a novel Ga source. Morphology, elemental composition, and crystallinity of the resulting nanowires are analyzed by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and selected area electron diffraction (SAED). Photoluminescence (PL) spectra of the Ga 2 O 3 nanowires show efficient defect-luminescence in the visible and UV ranges with blue and green emission peaks at 430 nm and 512 nm, respectively, at room temperature.

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