Wei Fen Jiang

Surface-enhanced Raman scattering of patterned copper nanostructure electrolessly plated on arrayed nanoporous silicon pillars

A new synthesized composite structure, a patterned copper/silicon nanoporous pillar array (Cu/Si-NPA) made by depositing Cu on Si-NPA using an immersion plating method, can be used as a surface-enhanced Raman scattering (SERS) substrate. Its surface component and morphology were analyzed by x-ray diffraction and field-emission scanning electron microscopy, respectively. It was found that the surface was Cu with two kinds of crystal structures: a continuous film composed of Cu nanocrystallites covering the Si-NPA, and a quasi-regular, interconnected network composed of loop-chains of Cu crystallites, with the size in the range of several tens of nanometer to 300 nm, surrounding the porous Si pillars. The composite structure is strongly SERS active using rhodamine 6G as probe molecules, which is mainly due to the patterned hierarchical Cu structure.

Study on the vacuum breakdown in field emission of a nest array of multi-walled carbon nanotube/silicon nanoporous pillar array

A composite structure, a nest array of multi-walled carbon nanotubes/silicon nanoporous pillar array (NACNT/Si-NPA), with good field emission properties, was synthesized through growing CNT on Si-NPA by thermal chemical vapor deposition. In order to make full use of its good field emission properties, the vacuum breakdown behavior accompanied with field emission from NACNT/Si-NPA was investigated. The results revealed that a positive feedback of field emission and resulted Joule heat ignited a small portion of protruding emitters, which caused spark discharge, destroyed the anode and generated a large amount of heat. The thermal runaway ultimately resulted in the destruction of substrate and vacuum breakdown.