Thermally and photoinduced structural and chemical changes of a silver nanocube array on Au(111).

We have investigated the thermally and photoinduced structural and chemical changes of a polyvinylpyrrolidone (PVP)-covered silver nanocube (AgNC) array on Au(111). The Langmuir-Blodgett (LB) method was utilized to fabricate the highly ordered array of the AgNC monolayer on Au(111). In the Raman spectra obtained at room temperature, sharp vibrational peaks were observed owing to the surface-enhanced Raman scattering (SERS) effect of AgNCs.

Stress-Induced In Situ Modification of Transition Temperature in VO Films Capped by Chalcogenide.

We attempted to modify the monoclinic-rutile structural phase transition temperature () of a VO thin film in situ through stress caused by amorphous-crystalline phase change of a chalcogenide layer on it. VO films on C- or R-plane AlO substrates were capped by GeSbTe (GST) films by means of rf magnetron sputtering. of the VO layer was evaluated through temperature-controlled measurements of optical reflection intensity and electrical resistance.

Localized electronic structures of graphene oxide studied using scanning tunneling microscopy and spectroscopy.

We have used scanning tunneling microscopy (STM) to elucidate the nanoscale electronic structures of graphene oxide (GO). The unreduced GO layer was imaged using STM without reduction processes when deposited on a Au(111) surface covered with an octanethiolate self-assembled monolayer (C8S-SAM). The STM image of the GO sheet exhibits a grainy structure having a thickness of about 1 nm, which is in good agreement with the previous results obtained using atomic force microscopy (AFM).

Pump-probe STM light emission spectroscopy for detection of photo-induced semiconductor-metal phase transition of VO.

We attempted to observe pump-probe scanning tunneling microscopy (STM)-light emission (LE) from a VO thin film grown on a rutile TiO(0 0 1) substrate, with an Ag tip fixed over a semiconducting domain. Laser pulses from a Ti:sapphire laser (wavelength 920 nm; pulse width less than 1.5 ps) irradiated the tip-sample gap as pump and probe light sources.

Selective scanning tunneling microscope light emission from rutile phase of VO2.

We observed scanning tunneling microscope light emission (STM-LE) induced by a tunneling current at the gap between an Ag tip and a VO2 thin film, in parallel to scanning tunneling spectroscopy (STS) profiles. The 34 nm thick VO2 film grown on a rutile TiO2 (0 0 1) substrate consisted of both rutile (R)- and monoclinic (M)-structure phases of a few 10 nm-sized domains at room temperature. We found that STM-LE with a certain photon energy of 2.

Nanoscale coupling of photons to vibrational excitation of Ag nanoparticle 2D array studied by scanning tunneling microscope light emission spectroscopy.

Scanning tunneling microscope light emission (STM-LE) spectroscopy has been utilized to elucidate the luminescence phenomena of Ag nanoparticles capped with myristate (myristate-capped AgNP) and 2-methyl-1-propanethiolate (C(4)S-capped AgNP) on the dodecanethiol-precovered Au substrate. The STM imaging revealed that myristate-capped AgNPs form an ordered hexagonal array whereas C(4)S-capped AgNPs show imperfect ordering, indicating that a shorter alkyl chain of C(4)S-capped AgNP is not sufficient to form rigid interdigitation. It should be noted that such a nanoparticle ordering affects the luminescence properties of the Ag nanoparticle.

Inelastic photoemission due to scattering by surface adsorbate vibrations.

By measuring the very low energy photoemission spectra of the CO/Cu(001) surface with a high resolution, we have found the energy loss components due to inelastic scattering of electrons near the Fermi level by the CO vibrational modes. The main energy loss structure appears as a step at 254 meV below the Fermi edge for 12C16O. An isotope shift of the step to 240 meV was observed when 13C18O was adsorbed.