Synthesis of palladium with different nanoscale structures by sputtering deposition onto fiber templates

A flexible and versatile method combining sputtering and electrospinning techniques was used to shape different palladium morphological structures with nanoscale features. The samples were prepared by dc-magnetron sputtering onto thermally degradable polymer templates. The sputtering parameters were chosen to deposit the metal under low adatom-mobility conditions. After deposition, the template was removed by heat treatment, thereby forming different palladium morphologies with shapes resembling ribbons and half tubes, amongst others. X-ray diffraction studies demonstrated that they are composed of crystalline palladium or palladium oxide, depending on the heat treatment. The cylindrical walls are composed of 30 nm or smaller crystallites, as measured from transmission electron microscopy images. A mathematical simulation demonstrate that the morphological structures obtained are a consequence of the sputtering line-of-sight deposition process. This fabrication process can be varied to modify three types of structures at the nanoscale level: the external shape, the columnar shape of the walls, and the nano-crystallinity. The external shape can be modified by controlling the deposition time and the fiber template diameter. The columnar shape of the walls and the nano-crystallinity can be modified by changes in the sputtering process parameters. The nanoscale morphologies created have potential uses in sensing and photonic applications.