Fabrication of Highly Ordered Dioctyl Diselenide Self-Assembled Monolayers Au(111)

Abstract

The surface structures and phase transitions of dioctyl diselenide (DODSe) self-assembled monolayers (SAMs) prepared by solution and ambient vapor deposition techniques on Au(111) were investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. Compare to the solution deposition of disordered DODSe SAMs on Au(111), vapor deposited DODSe SAMs are composed of well ordered phase and less number of vacancy islands (VIs). We revealed the phase transitions of DODSe SAMs from molecular aggregations to disordered dense phases via less dense missing-row phases. We also found that deposition time and temperature are critical factors for determining the surface structures of DODSe SAMs in ambient vapor-pressure deposition.