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The optimization of diamond films as valuable engineering materials for a wide variety of applications has required the development of robust methods for their characterization. Of the many methods used, Raman microscopy is perhaps the most valuable because it provides readily distinguishable signatures of each of the different forms of carbon (e.g. diamond, graphite, buckyballs). In addition it is non-destructive, requires little or no specimen preparation, is performed in air and can produce spatially resolved maps of the different forms of carbon within a specimen. This article begins by reviewing the strengths (and some of the pitfalls) of the Raman technique for the analysis of diamond and diamond films and surveys some of the latest developments (for example, surface-enhanced Raman and ultraviolet Raman spectroscopy) which hold the promise of providing a more profound understanding of the outstanding properties of these materials. The remainder of the article is devoted to the uses of Raman spectroscopy in diamond science and technology. Topics covered include using Raman spectroscopy to assess stress, crystalline perfection, phase purity, crystallite size, point defects and doping in diamond and diamond films.

Reverse bias current-voltage measurements of ϳ100-m-diameter gold Schottky contacts deposited on as-received, n-type ZnO(0001) wafers and those exposed for 30 min to a remote 20% O 2 /80% He plasma at 525Ϯ20°C and cooled either in vacuum from 425°C or the unignited plasma gas have been determined. Plasma cleaning resulted in highly ordered, stoichiometric, and smooth surfaces. Contacts on as-received material showed A leakage currents and ideality factors Ͼ2. Contacts on plasma-cleaned wafers cooled in vacuum showed ϳ36Ϯ1 nA leakage current to Ϫ4 V, a barrier height of 0.67Ϯ0.05 eV, and an ideality factor of 1.86Ϯ0.05. Cooling in the unignited plasma gas coupled with a 30 s exposure to the plasma at room temperature resulted in decreases in these parameters to ϳ20 pA to Ϫ7 V, 0.60Ϯ0.05 eV, and 1.03Ϯ0.05, respectively. Differences in the measured and theoretical barrier heights indicate interface states. ͑0001͒ and (0001) are used in this letter to designate the polar zinc-and oxygen-terminated surfaces, respectively.

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Tellurium-modified silicon nanowires with a large negative temperature coefficient of resistance Appl. Phys. Lett. 101, 133111 (2012) Tapered and aperiodic silicon nanostructures with very low reflectance for solar hydrogen evolution Appl. Phys. Lett. 101, 133906 (2012) Minimizing scattering from antireflective surfaces replicated from low-aspect-ratio black silicon Appl. Phys. Lett. 101, 131902 (2012) Robust hydrophobic Fe-based amorphous coating by thermal spraying Appl. Phys. Lett. 101, 121603 (2012) Influence of high temperature on solid state nuclear track detector parameters Rev. Sci. Instrum. 83, 093502 (2012) Additional information on J. Appl. Phys.Successful ex situ and in situ cleaning procedures for AlN and GaN surfaces have been investigated and achieved. Exposure to HF and HCl solutions produced the lowest coverages of oxygen on AlN and GaN surfaces, respectively. However, significant amounts of residual F and Cl were detected. These halogens tie up dangling bonds at the nitride surfaces hindering reoxidation. The desorption of F required temperatures Ͼ850°C. Remote H plasma exposure was effective for removing halogens and hydrocarbons from the surfaces of both nitrides at 450°C, but was not efficient for oxide removal. Annealing GaN in NH 3 at 700-800°C produced atomically clean as well as stoichiometric GaN surfaces.