Preparation and characterization of gold nanocrystals on NaCl(100) surfaces as labels for the dynamical x-ray tracking technique

We report on the fabrication of single crystalline gold nanocrystals of sizes between 10 nm and 25 nm. Gold was deposited under ultra high vacuum conditions on a freshly-cleaved NaCl(001) surface by means of the Molecular Beam Epitaxy technique. The preparation parameters substrate temperature and average thickness of the deposited gold were studied systematically. After the preparation, the crystals were characterized by means of different techniques, such as Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), X-Ray Diffractometry (XRD) and Laue Diffractometry.Measurements of the deposited cluster size, as measured by AFM, and the crystal size, as measured by XRD exhibited similar results at substrate temperatures between approx. 200 °C and 250 °C, indicating a high amount of single gold crystals. TEM images of gold crystals, made after the gold crystals had been dissolved in an aqueous 3-[(3-cholamidopropyl)dimethyl-ammonio]propane solution, support these results.Further, an effect of the substrate temperature during the deposition on the orientation of the gold crystals with respect to the NaCl(001) surface was observed. XRD measurements reveal a perpendicular texture of Au(111) parallel to NaCl(001) at approximately 310 °C. The second detected texture:Au(001)||NaCl(001) (in plane) and Au[100]||NaCl[100] (perpendicular) was observed over the complete studied temperature range (180 °C–330 °C).