A tunnel current in self-assembled monolayers of 3-mercaptopropyltrimethoxysilane

The use of alkanethiol monolayers on gold substrates and the monolayers formed by attachment of organic molecules with SiO2/Si or Si substrates by silanization, for designing resonant tunneling devices, was analyzed. The self-assembled-monolayer (SAM), 3-mercapto propyl tri methoxy silane (MPTMS) was taken for experiment which prevented diffusion of Au counterelectrode due to strong chemical bonding between S and Au. The SAMs of MPTMS molecules were synthesized by vapor-phase decomposition technique and thickness was determined by ellipsometry. The observations that taken by atomic force microscopy shows average surface roughness of 0.14 nm and X-ray photoelectron spectroscopic studies indicated an increase in S:C ratio from 0.19 to 0.23 with increase in take-off angle. It is also shown that tunneling is independent of temperature but depends on bias range. The results show that molecular monolayers could be used as gate dielectric well below limits of si-based dielectrics.