Optical absorption of transition-metal island films: Correlation interaction between conduction electrons of transition metals

Abstract

Optical plasma-resonance absorption of Pt island films consisting of Pt particles larger than about 25 Å in diameter has been measured in the photon energy range of 0.5-6.5 eV. As in Rh and Pd island films reported previously, the broadening of the optical plasma-resonance absorption reflects a correlation interaction between conduction electrons. Comparison of the broadening for the Pt island films with that for the Rh island films shows that the correlation interaction is strong when the conduction-electron density n is low. In an electron-gas model, the correlation interaction between electrons becomes stronger with lowering electron density, because the magnitude ratio of the Coulomb to kinetic energy increases as the electron density lowers. Thus, the strong correlation-interaction at low n proves that the correlation interaction in transition metals becomes stronger with magnitude ratio. The magnitude ratio in transition metals is pointed out to increase with lowering n and/or with strengthening d character of conduction electrons. Based on the correlation interaction, reflected by the broadening for the Pt, Rh, and Pd island films, and on the strong correlation interaction, found previously for Ir, the order of magnitude ratio is IrϾPtϾPdϾRh.

Giant enhancement of bandgap emission of ZnO nanorods by platinum nanoparticles

“…For all different sputtering times, a rather strong absorption band around the bandgap emission of ZnO nanorods at 380 nm has been found; it becomes more pronounced as the sputtering time is increased. According to the previous reports [13][14][15][16][17], the absorption band may be related to the surface plasmon resonance and interband transitions of Pt nanoparticles. These spectra provide an important clue for the understanding of the increased PL intensity as observed in figure 3.…”

Formation of self-organized platinum nanoparticles and their microphotoluminescence enhancement in the visible light region

“…This result is in line with previous research. 13 The investigation using the XPS and XRD measurements suggests that the composition of the nanoisland films and the nanoparticles mainly consist of Pt. As a result, we believe that their optical properties as measured by micro-PL should be related to their surface morphology.…”

“…The purpose of the SOG film spun on the silicon substrates was to prevent the formation of PtSi alloy or other platinum silicides when the Pt thin film was annealed. 13 The samples on the quartz substrates were prepared by the same procedure as those on the Si substrates. After annealing for 5 min, Pt islands in the nanometer range were formed.…”

Microstructure and percolation threshold characteristics of reactive sputtered Au–TiO2 granular composite films

“…Nanosized metallic particles exhibit large enhancement of local field due to the plasmon resonant absorption [1][2][3]. The metallic particle and dielectric composite materials show abnormal absorption and large nonlinearity, which have great potential applications in optical information processing and biosensor [4,5].…”