We report on position and density control of nitrogen-vacancy (NV) centres created in type Ib diamond using localised exposure from a helium ion microscope and subsequent annealing. Spatial control to <380 nm has been achieved. We show that the fluorescence lifetime of the created centres decreases with increasing ion dose. Furthermore, we show that for doses >1 Â 10 17 ion/cm 2 , significant damage of the diamond lattice occurs resulting in fluorescence quenching and amorphization. This places an upper limit on the density of NV centres that can be created using this method. V

Highly ordered self-assembled silver nanoparticle (NP) arrays have been produced by glancing angle deposition on faceted c-plane Al 2 O 3 templates. The NP shape can be tuned by changing the substrate temperature during deposition. Reflectance anisotropy spectroscopy has been used to monitor the plasmonic evolution of the sample during the growth. The structures showed a strong dichroic response related to NP anisotropy and dipolar coupling. Furthermore, multipolar resonances due to sharp edge effects between NP and substrate were observed. Analytical and numerical methods have been used to explain the results and extract semi-quantitative information on the morphology of the NPs. The results provide insight on the growth mechanisms by the glancing angle deposition. Finally, it has been shown that the NP morphology can be manipulated by a simple illumination the surface with an intense light source, inducing changes in the optical response. This opens up new possibilities for engineering plasmonic structure over large active areas.

We report for the first time the observation of bunching of monoatomic steps on vicinal W(110) surfaces induced by step up or step down currents across the steps. Measurements reveal that the size scaling exponent γ, connecting the maximal slope of a bunch with its height, differs depending on the current direction. We provide a numerical perspective by using an atomistic scale model with a conserved surface flux to mimic experimental conditions, and also for the first time show that there is an interval of parameters in which the vicinal surface is unstable against step bunching for both directions of the adatom drift.

A relatively simple method for preparation of planar nanowire arrays on vicinal substrates by molecular beam epitaxy is presented. The atomic step-and-terrace morphology of vicinal substrates is used to produce a shadowing effect on a highly collimated molecular beam at an oblique incidence to the substrate. The collimation is achieved by placing the evaporation source at a large working distance ͑40-100 cm͒ from the substrate. The method's capabilities have been demonstrated by preparation of arrays of Ag and Au nanowires on vicinal Si͑111͒ and ␣-Al 2 O 3 ͑0001͒ substrates. Nanowires with a width of down to 10-15 nm and a thickness of 1.5 nm have been readily achieved. The bottom-up approach to the fabrication of nanostructures has become a popular subject in current science and engineering. In particular, there has been substantial interest in the fabrication of nanowires of many different materials, driven by a wide range of potential applications. These nanowires come in many shapes and sizes but for nanowires formed by molecular beam epitaxy ͑MBE͒ on a substrate we can identify two principal geometries, i.e., either out of the substrate surface, 1,2 or in plane with the surface, e.g., planar nanowires grown on vicinal surfaces by the step-flow growth mechanism.3,4 The latter are particularly interesting from the point of view of planar electronic applications. However, preparation of nanowires by the step-flow growth mechanism is restricted in that it only works well for certain materials on certain metal or semiconductor surfaces. This is unfortunate if one is interested, for example, in utilizing the insulating properties of an oxide substrate. To overcome this difficulty, we look on to utilizing the shadowing effect of the step-andterrace morphology of a vicinal surface on a molecular beam at oblique incidence to the substrate surface. We term this approach atomic-terrace low-angle shadowing ͑ATLAS͒. This method utilizes the advantages of the bottom-up fabrication and its principal attraction is its relative simplicity. The method does not involve multiple lithography steps and can be applied to metal, semiconductor, or oxide surfaces alike, thus, making it potentially interesting for practical applications.5 Vicinal surfaces can be formed by annealing a surface that is off cut from a low-index orientation. [6][7][8] It is composed of atomic terraces separated by steps. The width of the atomic terraces can be readily controlled by the off-cut angle. Therefore, the separation between the nanowires within the array and their width could be readily controlled.The schematic of the ATLAS technique is shown in Fig.