This paper discusses the fundamentals, applications, potential, limitations, and future perspectives of polarized light reflection techniques for the characterization of materials and related systems and devices at the nanoscale. These techniques include spectroscopic ellipsometry, polarimetry, and reflectance anisotropy. We give an overview of the various ellipsometry strategies for the measurement and analysis of nanometric films, metal nanoparticles and nanowires, semiconductor nanocrystals, and submicron periodic structures. We show that ellipsometry is capable of more than the determination of thickness and optical properties, and it can be exploited to gain information about process control, geometry factors, anisotropy, defects, and quantum confinement effects of nanostructures.

Using Raman backscattering spectroscopy we have observed six local vibrational modes in as-grown state-of-the-art nominally undoped zinc oxide single crystals. The local vibrational modes are located at nu=2854, 2890, 2918, 2948, 2988, and 3096 cm(-1). Some specimens were annealed up to 950 degrees C to remove hydrogen. A subsequent Raman backscattering measurement revealed that the local vibrational modes disappeared. This establishes that the observed local vibrational modes are caused by the presence of hydrogen in the ZnO crystals.

We present the results of a depth-resolved cathodoluminescence (CL) and transmission electron microscopy study of autodoped GaN grown on sapphire. Depth-resolved CL analysis can be used for depth profiling of the yellow luminescence (YL) center concentration which was found to increase with depth. The results are consistent with the (ON–VGa)2− complex model of YL centers [J. Neugebauer and C. G. Van de Walle, Appl. Phys. Lett. 69, 503 (1996) and T. Mattila and R. M. Nieminen, Phys. Rev. B 55, 9571 (1996)]. Depth profiling of the near-edge emission in GaN layers thicker than ∼0.5 μm is not possible due to strong self-absorption.

The delafossite structured CuCrO 2 system is well known as one of the best performing p-type transparent conducting oxides. In this paper the details of a low temperature facile growth method for CuCrO 2 is described. The dependence of the growth on the precursors, the temperature and oxygen partial pressure are examined. The decomposition routes are critical to obtain the best performing films. The thermopower and electrical measurements indicate p-type films with conductivity ranging from 1-12 Scm −1 depending on the growth conditions. This p-type conductivity is retained despite the nanocrystallinity of the films. The figure of merit of these films can be as high as 350 µS, which is the best performing p-type TCO by solution methods to date. The optical properties are also investigated using ellipsometry and UV-Vis spectroscopy.

The rapidly expanding fields of bioelectronics, and biological interfaces with sensors and stimulators, are placing an increasing demand on candidate materials to serve as robust surfaces that are both biocompatible, stable and electroconductive.

One-dimensional Ag nanoparticle arrays have been grown on step-bunched vicinal Al 2 O 3 in ultrahigh vacuum using deposition at a glancing angle. The structures grown showed a strong optical anisotropy in the visible region of the spectrum. The optical anisotropy was measured in situ using reflection anisotropy spectroscopy. Relevant optical properties were determined as a function of deposition angle and Ag thickness. A simple phenomenological model was developed to reproduce the features seen in the spectra. With this model it was possible to use the inhomogeneous broadening as a guide to the nanoparticle dispersion.

Metal-free carbon electrodes with well-defined composition and smooth topography were prepared via sputter deposition followed by thermal treatment with inert and reactive gases. XPS and Raman spectroscopies show that three carbons of similar N/C content that differ in Nsite composition were thus prepared: an electrode consisting of almost exclusively graphitic-N (NG), an electrode with predominantly pyridinic-N (NP) and one with ca. 1:1 NG:NP composition. These materials were used as model systems to investigate activity of N-doped carbons in the oxygen reduction reaction (ORR) using voltammetry. Results show that selectivity towards 4e-reduction of O2 is strongly influenced by the NG/NP site composition, with the material possessing nearly uniform NG/NP composition being the only one yielding a 4e-reduction. Computational studies on model graphene clusters were carried out to elucidate the effect of N-site homogeneity on the reaction pathway. Calculations show that for pure NGdoping or NP-doping of model graphene clusters, adsorption of hydroperoxide and hydroperoxyl radical intermediates, respectively, is weak thus favoring desorption prior to complete 4e-reduction to hydroxide. Clusters with mixed NG/NP sites display synergistic effects, suggesting that co-presence of these sites improves activity and selectivity by achieving high theoretical reduction potentials while facilitating retention of intermediates.

Epitaxial p-type transparent conducting oxide (TCO) Cr 2 O 3 :Mg was grown by electron-beam evaporation in a molecular beam epitaxy system on c-plane sapphire. The influence of Mg dopants and the oxygen partial pressure were investigated by thermoelectric and electrical measurements. The conduction mechanism is analyzed using the small-polaron hopping model, and hopping activation energies have been determined, which vary with doping concentration in the range of 210-300 ± 5 meV. Films with better conductivity were obtained by postannealing. The effect of postannealing is discussed in terms of a crystallographic reordering of the Mg dopant. The highest Seebeck mobilities obtained from thermoelectric measurements are of the order of 10 −4 cm 2 V −1 s −1 . We investigate the fundamental properties of a Mg dopant in a high crystalline quality epitaxial film of a binary oxide, helping us understand the role of short range crystallographic order in a p-type TCO in detail.