Laser ablation preparation

Alternative Thin-Film Fabrication Approaches. Thin films of electronic ceramic materials have also been prepared by sputtering, electron beam evaporation, laser ablation, chemical beam deposition, and chemical vapor deposition (CVD). In the sputtering process, targets may be metal... 

Direct sampling of solids may be carried out using laser ablation. In this technique a high-power laser, usually a pulsed Nd-YAG laser, is used to vaporize the solid, which is then swept into the plasma for ionization. Besides not requiring dissolution or other chemistry to be performed on the sample, laser ablation ICPMS (LA-ICPMS) allows spatial resolution of 20-50 pm. Depth resolution is 1-10 pm per pulse. This aspect gives LA-ICPMS unique dit nostic capabilities for geologic samples, surface features, and other inhomogeneous samples. In addition minimal, or no, sample preparation is required. 

Historically, AuF has been one of the most elusive of all metal halides. At one time it was believed to be impossible to prepare, and theoretical papers speculating on how it might be observed or predicting spectroscopic and structural properties have been published until recently.3075- 1 The existence of AuF has been confirmed by microwave spectroscopy, the sample has been prepared by laser ablation of Au metal in the presence of a F precursor.3082 The gas-phase structure of Aul has also been determined by microwave spectroscopy.3083... 

Mass spectrometric measurements of ions desorbed/ionized from a surface by a laser beam was first performed in 1963 by Honig and Woolston [151], who utilized a pulsed mby laser with 50 p,s pulse length. Hillenkamp et al. used microscope optics to focus the laser beam diameter to 0.5 p,m [152], allowing for surface analysis with high spatial resolution. In 1978 Posthumus et al. [153] demonstrated that laser desorption /ionization (LDI, also commonly referred to as laser ionization or laser ablation) could produce spectra of nonvolatile compounds with mass > 1 kDa. For a detailed review of the early development of LDI, see Reference 154. There is no principal difference between an LDI source and a MALDI source, which is described in detail in Section 2.1.22 In LDI no particular sample preparation is required (contrary to... 

Imanishi N, Matsumura T, Sumiya Y, Yoshimura K, Hirano A, Takeda Y et al. Impedance spectroscopy of perovskite air electrodes for SOFC preparated by laser ablation method. Solid State Ionics 2004 174 245-252. 

The titanosilicate version of UTD-1 has been shown to be an effective catalyst for the oxidation of alkanes, alkenes, and alcohols (77-79) by using peroxides as the oxidant. The large pores of Ti-UTD-1 readily accommodate large molecules such as 2,6-di-ferf-butylphenol (2,6-DTBP). The bulky 2,6-DTBP substrate can be converted to the corresponding quinone with activity and selectivity comparable to the mesoporous catalysts Ti-MCM-41 and Ti-HMS (80), where HMS = hexagonal mesoporous silica. Both Ti-UTD-1 and UTD-1 have also been prepared as oriented thin films via a laser ablation technique (81-85). Continuous UTD-1 membranes with the channels oriented normal to the substrate surface have been employed in a catalytic oxidation-separation process (82). At room temperature, a cyclohexene-ferf-butylhydroperoxide was passed through the membrane and epoxidation products were trapped on the down stream side. The UTD-1 membranes supported on metal frits have also been evaluated for the separation of linear paraffins and aromatics (83). In a model separation of n-hexane and toluene, enhanced permeation of the linear alkane was observed. Oriented UTD-1 films have also been evenly coated on small 3D objects such as glass and metal beads (84, 85). 

Huang and Freiser (132, 133) were able to prepare exohedral metal C60 ions [MC60]+ by direct reaction of the bare metal ions Fe+, Ni+, Co+, Cu+, Rh+, and La+ with Cgo vapor produced from a heated probe. The [MC60]+ ions when subjected to low-energy collision-induced dissociation with argon all produced the Cg0 ion. These results show that the metal ions attach to the outer surface of C60. The exohedral metallofullerene ions differ from the endohedral metallofullerenes produced by laser ablation of metal oxide-graphite mixtures and support the observations of Smalley and co-workers (148) who found that endohedral metallofullerene ions dissociate by loss of C2 units. 

Laser ablation ICP-MS (LA-ICP-MS) was established in the early 1990s as a potential routine tool for the measurement of trace and ultra-trace elements in silicate systems for geology. Early studies (Perkins et al. 1993) used sample preparation techniques identical to that used to prepare rock samples for WDXRF, i.e., either a pressed powder disk or a glass bead fusion method (see Appendix VIII). Such studies concluded that LA-ICP-MS had the potential to surpass XRF in terms of the limits of detection achieved and INAA in terms of the speed of analysis (Perkins et al. 1993 481). It has long been recognized that the main limit on the quantitative performance of LA-ICP-MS is the homogeneity at the trace and ultra-trace level of the solid calibration standards available. Subsequent work (e.g., Hollecher and Ruiz 1995, Norman et al. 1996) has demonstrated that some of the international... 

CNTs are prepared by either laser ablation from graphite target, arc discharge, or chemical vapor deposition. In either case, to grow they need the presence of Co or Ni catalyst. Typically, outer diameter of CNTs prepared by a carbon arc process ranges between 20 and 200 A, and inner diameter ranges between 10 and 30 A. An aspect ratio (length-to-diameter ratio) is typically of 10 -10. ... 

Harano A, Shimada K, Okubo T, Sadakata M. (2002) Crystal phases of Ti02 ultrafine particles prepared by laser ablation of solid rods. J Nanoparticle Res 4 215-219... 

Iwabuchi A, Choo CK, Tanaka K Titania Nanoparticles Prepared with Pulsed Laser Ablation of Rutile Single Crystals in Water J Phys Chem B 108 10863-10871... 

The method of laser ablation from a metal has been used to prepare nanoparticles dispersed in a solution [202-207]. Recently, colloidal gold nanoparticles in water having an average diameter of 5.5 nm were prepared by laser ablation at 1064 nm (800 mJ/cm ) from a gold metal plate [208]. The final nanoparticle size depends on the laser fluence and the stabilizer concentration (Fig. 17). 

Mafune F, KohnoJ Y, Takeda Y, Kondow T (2002) Fnll physical preparation of size-selected gold nanoparticles in solntion Laser ablation and laser-indnced size control. J Phys Chem B 106 7575-7577... 

There have been some reports of superconducting thin films of Nd2 xCexCu04 prepared by laser ablation (38)(39). The films are prepared from sintered Nd1 5Ce015Cu04 targets on heated (100)-SrTiOs substrates. Typical conditions are 500°C at an ambient oxygen pressure of 10"4 atm, followed by annealing at 900°C. 

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