Self-assembly of Silver Nanoparticles and Multiwall Carbon Nanotubes on Decomposed GaAs Surfaces

Atomic Force Microscopy complemented by Photoluminescence and Reflection High Energy Electron Diffraction has been used to study self-assembly of silver nanoparticles and multiwall carbon nanotubes on thermally decomposed GaAs (100) surfaces. It has been shown that the decomposition leads to the formation of arsenic plate-like structures. Multiwall carbon nanotubes spin coated on the decomposed surfaces were mostly found to occupy the depressions between the plates and formed boundaries. While direct casting of silver nanoparticles is found to induce microdroplets. Annealing at 300°C was observed to contract the microdroplets into combined structures consisting of silver spots surrounded by silver rings. Moreover, casting of colloidal suspension consists of multiwall carbon nanotubes and silver nanoparticles is observed to cause the formation of 2D compact islands. Depending on the multiwall carbon nanotubes diameter, GaAs/multiwall carbon nanotubes/silver system exhibited photoluminescence with varying strength. Such assembly provides a possible bottom up facile way of roughness controlled fabrication of plasmonic systems on GaAs surfaces

Properties and dynamics of the image potential states on graphite investigated by multiphoton photoemission spectroscopy

Lehmann J, Merschdorf M, Thon A, Voll S, Pfeiffer W. Properties and dynamics of the image potential states on graphite investigated by multiphoton photoemission spectroscopy. Phys. Rev. B. 1999;60(24):17037-17045

Silver nanoparticles on graphite studied by femtosecond time-resolved multiphoton photoemission

Lehmann J, Merschdorf M, Pfeiffer W, Thon A, Voll S, Gerber G. Silver nanoparticles on graphite studied by femtosecond time-resolved multiphoton photoemission. J. Chem. Phys. 2000;112(12):5428

Surface plasmon dynamics in silver nanoparticles studied by femtosecond time-resolved photoemission

Lehmann J, Merschdorf M, Pfeiffer W, Thon A, Voll S, Gerber G. Surface plasmon dynamics in silver nanoparticles studied by femtosecond time-resolved photoemission. Phys. Rev. Lett. 2000;85(14):2921-2924.Multiphoton photoelectron spectroscopy reveals the multiple excitation of the surface plasmon in silver nanoparticles on graphite. Resonant excitation of the surface plasmon with 400 nm femtosecond radiation allows one to distinguish between photoemission from the nanoparticles and the substrate. Two different previously unobserved decay channels of the collective excitation have been identified, namely, decay into one or several single-particle excitations

Time-resolved two-photon photoemission spectroscopy of HOPG and Ag nanoparticles on HOPG

Ertel K, Kohl U, Lehmann J, et al. Time-resolved two-photon photoemission spectroscopy of HOPG and Ag nanoparticles on HOPG. Appl. Phys. B. 1999;68(3):439-445.Time-resolved two-color two-photon photoemission experiments are used to investigate the electronic dynamics in highly oriented pyrolytic graphite (HOPG) and in Ag nanoparticles grown on HOPG. The multiphoton photoemission using 267 nm and 400 nm excitation is presented and discussed. For the first time the known unoccupied state on graphite 3.6 eV above the Fermi level can be identified as an image potential state. A lower limit of 60 fs is given for the lifetime of this state. The two-color experiments reveal that the carrier relaxation deduced from time-resolved experiments is influenced by feeding of the intermediate states. First results of the strongly enhanced multiphoton photoemission from Ag nanoparticles on HOPG at 400 nm wavelength are presented. This observation is explained by the excitation of the surface plasmon and its subsequent decay

Femtosecond multiphoton photoemission of silver nanoparticles on graphite

Voll S, Lehmann J, Merschdorf M, Pfeiffer W, Thon A, Gerber G. Femtosecond multiphoton photoemission of silver nanoparticles on graphite. Presented at the Multiphoton Processes ICOMP VIII 8th Int. Conf