Pulsed laser ablation of Sn and SnO2 targets: Neutral composition, energetics, and wavelength dependence

We report time-of-flight mass spectrometric studies of neutral gas-phase sp ecies generated in 532 and 355 nm laser ablation of Sn and SnO2 targets at intensities of approximate to 10(8) W cm(-2), below the plasma threshold. A wavelength-dependent yield of Sn:SnxOy species is observed for the oxide t arget, with SnxOx (x = 1-3) the primary products at 532 nm and atomic Sn do minant at 355 nm. Sn and Sn-2 are the primary products of Sn metal ablation , and the relative Sn:Sn-2 yield increases at the shorter wavelength. The s peed distributions of neutrals ejected from the oxide target are well repre sented 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) x 10(5) cm s(-1), with peak kinetic energies (KEs) of 1-2 eV. The implications of our results for pulsed laser deposition of SnOx films will be emphasized.