Applied Surface Science, Vol.255, No.4, 824-827, 2008
Molecular ion yield enhancement induced by gold deposition in static secondary ion mass spectrometry
Static ToF-SIMS was used to evaluate the effect of gold condensation as a sample treatment prior to analysis. The experiments were carried out with a model molecular layer (Triacontane M = 422.4 Da), upon atomic (In+) and polyatomic (Bi-3(+)) projectile bombardment. The results indicate that the effect of molecular ion yield improvement using gold metallization exists only under atomic projectile impact. While the quasi-molecular ion (M+Au)(+) signal can become two orders of magnitude larger than that of the deprotonated molecular ion from the pristine sample under In+ bombardment, it barely reaches the initial intensity of (M-H)(+) when Bi-3(+) projectiles are used. The differences observed for mono- and polyatomic primary ion bombardment might be explained by differences in near-surface energy deposition, which influences the sputtering and ionization processes. (c) 2008 Elsevier B.V. All rights reserved.