The ion beam deposition (IBD) of rhodamine dye molecules on solid surfaces in high vacuum is explored in order to characterize the possibility of fabricating molecular coatings or nanostructures from nonvolatile molecules. Molecular ion beams with a well-defined composition are deposited on silicon oxide surfaces with a controlled kinetic energy. Photoluminescence spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS) are employed in order to characterize the sample with respect to coverage, homogeneity, and the fraction of intact landed ions (soft-landing ratio). We find that homogeneous rhodamine films of defined composition can be produced at energies of 2؊100 eV. The coverage is found to be proportional to the ion dose. Soft-landing is observed for energies up to 35 eV.

SiO2 is the most widely used dielectric material but its growth or deposition involves high thermal budgets or suffers from shadowing effects. The low-temperature method presented here (150 degrees C) for the preparation of SiO2 by thermal atomic layer deposition (ALD) provides perfect uniformity and surface coverage even into nanoscale pores, which may well suit recent demands in nanoelectronics and nanotechnology. The ALD reaction based on 3-aminopropyltriethoxysilane, water, and ozone provides outstanding SiO2 quality and is free of catalysts or corrosive by-products. A variety of optical, structural, and electrical properties are investigated by means of infrared spectroscopy, UV-Vis spectroscopy, secondary ion mass spectrometry, capacitance-voltage and current-voltage measurements, electron spin resonance, Rutherford backscattering, elastic recoil detection analysis, atomic force microscopy, and variable angle spectroscopic ellipsometry. Many features, such as the optical constants (n, k) and optical transmission and surface roughness (1.5 A degrees), are found to be similar to thermal oxide quality. Rapid thermal annealing (RTA) at 1000 degrees C is demonstrated to significantly improve certain properties, in particular by reducing the etch rate in hydrofluoric acid, oxide charges, and interface defects. Besides a small amount of OH groups and a few atomic per mille of nitrogen in the oxide remaining from the growth and curable by RTA no impurities could be traced. Altogether, the data point to a first reliable low temperature ALD-growth process for silicon dioxide

GdN thin films are deposited on MgO(100) by low-energy ion-beam-assisted molecular-beam epitaxy at elevated temperatures. Elemental analysis by secondary-ion mass spectrometry proves that a protective layer is imperative to avoid oxidation of the GdN films in air. In situ surface structural investigation of the growing GdN films by reflection high-energy electron diffraction reveals epitaxial film growth. This result is confirmed by x-ray diffraction structure and texture analysis. Accordingly, the GdN films on MgO(100) exhibit cube-on-cube epitaxy. Due to the epitaxial growth the crystalline quality of the films is by far higher than that of films previously reported of in literature.

The influence of the high-temperature annealing ambient, i.e., N 2 and Ar on size controlled Si nanocrystals ͑NCs͒ ranging from ϳ2 to ϳ6 nm embedded in SiO 2 has been investigated in detail. Generally, N 2 annealing is proven to be beneficial as the dangling bond density ͑P b defects at the NC/ SiO 2 interface͒ is about half, accompanied by a doubled photoluminescence ͑PL͒ intensity. The PL blueshift of N 2 annealed samples compared to Ar-annealed samples ͑N-blueshift͒ was found to be pronounced only for small NCs whereas it appears to be insignificant for larger NCs. The origin of this N-blueshift was previously attributed to a growth suppression of the NCs by the presence of N during the annealing process. However, no evidence for this assumption is found by time-resolved PL, as the luminescence decay times are similar despite considerable N-blueshift. The exact location of the N incorporated during annealing was investigated by time-of-flight-SIMS and electron-spin resonance. Besides the distinct N enrichment in the NC layer, the K 0 center ͑ • Si ϵ N 3 ͒ was detected indicating the formation of an interfacial N layer at the NC/ SiO 2 interface. Elastic recoil detection analysis enabled the quantification of the incorporated N as well as the excess Si. Combined with transmission electron microscopy analysis ͑determination of NC size͒ the calculation of the NC density per superlattice layer and the thickness of the interfacial N layer were achieved. It turns out that ϳ5 ϫ 10 14 N atoms cm −2 exist at the NC surface, which is well in accordance to the optimum value of the bulk Si/ SiO 2 interface. These results strongly support our recently suggested explanation for the N-blueshift that is based on an increased NC band gap by the influence of interfacial N on the polarity of the surface terminating groups.

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