Alkanethiol Self-Assembled Monolayers Formed on Silicon Substrates

We have prepared alkanethiol monolayers, directly attached to a silicon substrate, by immersing hydrogen-terminated silicon in 1-hexadecanethiol solution at 150 degrees C. The evidence for the 1-hexadecanethiol monolayer formation was obtained and the resulting monolayers were compared with the monolayers formed from 1-hexadecanol using water contact angle measurements, X-ray photoelectron spectroscopy, ellipsometry, and atomic force microscopy. The densities of the alkyl chains in the 1-hexadecanethiol monolayers were lower than those of the 1-hexadecanol monolayer. The durability of these monolayers to 5% HF aqueous solution was also examined. The 1-hexadecanethiol monolayer is found to be less durable than the 1-hexadecanol monolayer. (C) 2010 The Japan Society of Applied Physics