Therefore, we directly micropipetted a YM155 colloidal silica sphere solution on the substrate squares with an area of 5 × 5 mm2. The Volasertib cost solution contained enough silica spheres to give a full monolayer of colloidal silica spheres. A small droplet of water (approximately 10 μl) was also placed on top of the colloidal solution on the substrates. The solution on top of STO has been dried under continuous sonication. AFM images of deposited silica layers were acquired with a Bruker AFM model Icon (Bruker, the Netherlands). The silicone cantilevers were purchased from MikroMasch

(Wetzlar, Germany) with a force constant of 14 N m−1. All images were acquired using tapping mode under ambient laboratory conditions. An epitaxial C646 concentration platinum film with a thickness of 8 nm was evaporated by e-beam evaporation using a three-step deposition technique [7]. A monolayer of silica beads was removed by sonication in hot concentrated potassium hydroxide aqueous solution. The nanocrystal arrays were characterized by X-ray diffraction

(XRD) to confirm the orientation of crystalline platinum islands with respect to the substrate. The diffraction experiments were performed at the Advanced Photon Source (APS) using the four-circle diffractometer with a vertical scattering geometry at beamline 12BM. The incident energy was 11.5 keV, and beam defining slits were set to 1 mm with an under-focused beam. From our experience, intense synchrotron X-ray beam in the presence of

oxygen from air causes damage to platinum single crystal surfaces. Most likely, this damage is a result of interaction between reactive free radicals generated from oxygen and platinum metal. We protected delicate nanocrystal arrays nearly from X-ray damage by flowing ultra-high purity nitrogen gas into a polypropylene bag placed over the sample. For the STO (001) substrates, the Pt (004) and four (113) Bragg peaks were found. It is necessary to use a θ-offset of 0.15° to 0.30° for the θ-2θ scans so that the STO Bragg peak does not saturate the scintillation detector and to reduce background around the platinum Bragg peaks (STO and Pt (004) are separated by approximately 0.3° at 11.5 keV). The samples were also characterized by a high-resolution Hitachi Model S4700 scanning electron microscope (Hitachi, Tokyo, Japan) at the Electron Microscopy Center, Argonne National Laboratory. Results and discussion Microscopy characterization of silica monolayers and platinum nanoparticle arrays Ordered silica bead monolayers, which later served as templates for the platinum metal deposition, were made by depositing solutions containing either 450- or 150-nm silica beads. We used AFM and optical microscopy to characterize deposited layers. Figure 1 shows optical microscopy image of 150-nm silica spheres deposited on STO.