Pulsed Laser Ablation of Sn and SnO₂ Targets:  Neutral Composition, Energetics, and Wavelength Dependence

Abstract

We report time-of-flight mass spectrometric studies of neutral gas-phase species generated in 532 and 355 nm laser ablation of Sn and SnO2 targets at intensities of ≈108 W cm-2, below the plasma threshold. A wavelength-dependent yield of Sn:Sn x O y species is observed for the oxide target, with Sn x O x (x = 1−3) the primary products at 532 nm and atomic Sn dominant at 355 nm. Sn and Sn2 are the primary products of Sn metal ablation, and the relative Sn:Sn2 yield increases at the shorter wavelength. The speed distributions of neutrals ejected from the oxide target are well represented by unshifted time-transformed Maxwell−Boltzmann (MB) distributions, while those ejected from the metal target exhibit bimodal MB distributions. Typical most-probable speeds are (1−2) × 105 cm s-1, with peak kinetic energies (KEs) of 1−2 eV. The implications of our results for pulsed laser deposition of SnO x films will be emphasized.

Resonant Laser Ablation of Metals Detected by Atomic Emission in a Microwave Plasma and by Inductively Coupled Plasma Mass Spectrometry

“…Normally, laser ablation for quantitative elemental analysis involves the use of high power, fixed wavelength, pulsed lasers for ablation of the sample. 1 Various laser wavelengths have been used including 1064 nm from a Nd:YAG laser, [2][3][4] or of harmonics [5][6][7] of the Nd:YAG, 532 nm, 355 nm, or 266 nm. Also, excimer lasers 8,9 have allowed ablation deeper into the ultraviolet (UV) down to 193 nm 10,11 and 157 nm.…”

Atomic Spectrometry Update. Atomic mass spectrometry

“…The scale of the challenge is demonstrated by the fact that v1100 atoms of 81 Kr l 21 were available for counting. This represents an activity of 1.1610 210 Bq or one radioactive decay every 300 yr. Although the feasibility of the method has been established, it was considered that ''routine'' measurements for groundwater samples of convenient size (10-20 l) still rested on major technical improvements.…”

“…Reid et al 210 investigated the wavelength dependence of the relative abundance of the neutrals generated from tin and tin dioxide by irradiation at a power density of about 10 8 W cm 22 , i.e., below the plasma threshold. The major species generated from the oxide target were Sn x O x (x~1-3) at a wavelength of 532 nm, whereas atomic Sn was dominant at a wavelength of 355 nm.…”

Resonant effects in nonlinear photon absorption during femtosecond laser ablation of Nd-doped silicate glass

“…RLA of different metallic materials has been investigated by nanosecond pulses from Nd:YAG-pumped dye lasers [7][8][9][10][11] or excimer-pumped dye lasers [12]. RLA of polymers by picosecond pulses from freeelectron lasers has also been studied [13,14].…”