A NEW SURFACE FOR SURFACE-ENHANCED INFRARED-SPECTROSCOPY - TIN ISLANDFILMS

For the first time, it has been observed that tin island films used in surface infrared experiments give rise to an electromagnetic enhancem ent of the infrared absorption spectrum. The surface enhancement of th e infrared (SEIR) absorption by tin island films is shown for evaporat ed nanometric films of 5,14-pentacenedione (Q2) and naphthalic 1,8:4,5 -dianhydride (NTCDA). The experiments and spectral characteristics dem onstrating the ability of tin to produce SEIR of organic molecules phy sically adsorbed onto tin structures are described. Tin island films o f varying mass thickness were fabricated to ascertain maximum enhancem ent. Their morphology was determined by transmission electron microsco py. Comparisons are made between the SEIR spectra on rough tin and on silver surfaces and the corresponding reflection-absorption spectra (R AIRS) obtained for the same organic molecules on reflecting surfaces o f tin and silver.