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GaN nanodots (NDs) are obtained by Ga metallic droplet formation on Si (1 1 1) substrates followed by their nitridation. The size and density of Ga droplets and GaN NDs can be controlled by varying the growth temperature within the range 514–640 °C. Atomic force microscopy (AFM) investigation of Ga droplets shows an increase in the average diameter with temperature. The average diameter of GaN NDs increases with growth temperature while their density decreases more than one order of magnitude. In addition, the formation of a GaN crystallite rough layer on Si, in-between NDs, indicates that a spreading mechanism takes place during the nitridation process. High-resolution transmission electron microscopy (HRTEM) is used for the investigation of shape, crystalline quality and surface distribution of GaN dots. X-ray photoelectron spectroscopy (XPS) results confirm that Ga droplets that are transformed into GaN NDs spread over the sample surface during nitridation.

The growth of InN using plasma-assisted MBE has been investigated within the parameter range of columnar growth to obtain uniform whiskers with a high crystalline quality. The column morphology and crystalline quality were investigated by scanning electron microscopy (SEM) and photoluminescence (PL), respectively. The PL peak energy varies in the range 0.76–0.82 eV, while the peak intensity changes more than two orders of magnitude with the growth conditions. The PL intensity increases with column length and growth temperature. These findings suggest higher crystalline quality and less intrinsic doping at higher growth temperature. Columns grown at higher temperatures are very nonuniform in diameter.

Morphology and optical properties of GaN nanowhiskers grown by molecular beam epitaxy (MBE) have been studied in correlation with growth parameters. It was shown that the growth parameters can be tuned such that uniform, well separated and high-quality nanowhiskers are obtained. Using an optimized ramp of Ga beam equivalent pressure (BEP) during the growth, the tapering or coalescence of nanowhiskers can be suppressed. By increasing the growth temperature the density of nanowhiskers is reduced, but the crystalline quality is improved as can be concluded from cathodoluminescence (CL) results.

Fe films of different thicknesses were deposited on wurtzite GaN(0 0 0 1) layers by electron beam evaporation. They were studied by a number of characterization techniques such as low-energy electron diffraction (LEED), X-ray diffraction (XRD), atomic force microscopy (AFM), Rutherford backscattering spectrometry (RBS), and ferromagnetic resonance (FMR). Despite the large lattice mismatch between Fe and wurtzite GaN a clear epitaxial relation was determined. Three distinct Fe domain orientations were found rotated by 120 ∘ relative to each other. Due to the formation of crystalline domains a hexagonal in-plane magnetic anisotropy was observed.