Polarized infrared reflectivity was measured between 5 and 300 K on a 17 nm thick, 1.1% compressively strained epitaxial (001) SrTiO(3) film and the orthorhombic (110) NdGaO(3) substrate upon which it was grown. A strong in-plane infrared anisotropy of the NdGaO(3) substrate was observed and polar modes with B(1u)-and a mixture of B(2u) + B(3u)-symmetry were seen. At low temperatures three new modes arose in the 90-130 cm( - 1) range, which we assigned to 4f Nd electronic transitions. The in-plane SrTiO(3) film phonons showed strong stiffening compared to the phonon frequencies of bulk unstrained SrTiO(3), particularly the soft mode, and the in-plane phonon peaks were found to split. No anomalies were detected as a function of temperature in either the infrared response or lattice parameters of the compressively strained SrTiO(3) film, providing an absence of evidence for the out-of-plane ferroelectric phase transition predicted by theory.

In this paper the growth of Ga droplets on a vicinal Si(111) surface is discussed. We report that the droplet size can be controlled down to the sub-100 nm range by carefully chosen deposition conditions. In addition, the dependence of the droplet size on deposition time is not monotonic, but shows self-limiting behaviour: with increasing amount of Ga on the surface the droplets stop increasing in lateral dimension and, instead, additional droplets of the same size are formed on the surface. Further, in the case of deposition at 300 °C substrate temperature it has been found that the growth proceeds in cycles. Thus, not only the size but also the droplet concentration can be controlled. In this way, non-ordered arrays of metallic droplets with a very narrow size distribution can be grown.