Characterization of nanostructured metal films by picosecond acoustics and interferometry

Abstract

Articles you may be interested inAcoustic interferometry for geoacoustic characterization in a soft-layered sediment environment J. Acoust. Soc. Am. 133, 82 (2013); 10.1121/1.4768879 Femtosecond laser-ultrasonic investigation of plasmonic fields on the metal/gallium nitride interface Appl. Phys. Lett. 97, 201102 (2010); 10.1063/1.3503633 Atomic diffusion bonding of wafers with thin nanocrystalline metal films Large excess volume in grain boundaries of stressed, nanocrystalline metallic thin films: Its effect on graingrowth kinetics Appl. Phys. Lett. 95, 163112 (2009); 10.1063/1.3248070 High-frequency surface acoustic wave propagation in nanostructures characterized by coherent extreme ultraviolet beams Appl. Phys. Lett. 94, 093103 (2009);Picosecond interferometry is used to study the acoustics waves created by heating Pt films with a subpicosecond laser pulse. Both the period of the initial oscillations in the metal film and the amplitude of the sound wave in the substrate are measured quantitatively. The platinum films are roughened by irradiation with energetic ions. The amplitude of the sound wave is doubled at those irradiation levels where the platinum coverage has been reduced by about one-half. A theory for the amplitude of the launched acoustic wave predicts that the acoustic amplitude is proportional to the mean square film thickness. Thus changes in the morphology of a partially perforated metal film can be observed using a simple, nondestructive optical technique.

Time-domain Brillouin scattering assisted by diffraction gratings

“…Picosecond acoustic interferometry (PAI) is a powerful opto-acousto-optic technique for nondestructive and noncontact testing of transparent materials at the nanoscale [1][2][3][4][5][6][7][8][9][10][11][12][13]. First, using an ultrashort pump laser pulse, a propagating picosecond coherent acoustic pulse (CAP) is launched into the material.…”

High-Amplitude, Ultrashort Strain Solitons in Solids

“…Analysis of thin-film and nanostructured media: Currently this is the principle research area that is actively being studied. Next to the analysis of one-dimensional multilayer structures ('nano-seismology'), attempts have been made to characterize the acoustic behavior of composite and nanostructured media [25][26][27]. Additionally, the shape of the generated strain pulses is used to deduce the electron dynamics [22,23,28], and to study the wavelength-dependent elasto-optic coupling parameters [29] of the metal film.…”

“…As an extension of conventional ultrasonics into the nanometer size-regime, the method of picosecond ultrasonics has found wide application as an imaging tool in scientific and industrial environments [20][21][22][23][24][25][26][27][28][29][30][31][32][33]. The small width of the strain pulses sets a limit to the spatial resolution that can otherwise only be achieved using x-ray radiation.…”

A simple calibration procedure to determine thermal effusivity values measured by using a thermal microscope

“…Further, they suggested that both the lasers must be fixed at a particular location in order to detect local clacks that may cause high thermal resistance. Haxtable et al, [5] Costescu et al, [6], and O'Hara et al [7] developed a measurement method to obtain the distribution of thermal conductivity on a small surface at the micrometer scale by using a time-domain thermoreflectance method. This method uses two synchro -nous short-pulse lasers, which are used to heat the sample surface and measure the resulting change in the reflectivity of the metal surface.…”