Electrical properties of single nitro oligophenylene ethynylene (OPE) molecule by using UHV STM

Self-assembled monolayers (SAMs) are ordered molecular structures formed by the adsorption of an active surfactant on a solidsurface. A SAM lm can be deposited on a substrate surface simply by exposing the surface to an environment containing surface-active molecular species for a certain period of time (solution or vapor phase deposition). The molecules will be spontaneously ori-ented toward the substrate surface and form an energetically favorable ordered layer. During this process, the surface-active headgroup of the molecule chemically reacts with and chemisorbs onto the substrate. In this paper, we conrmed the electrical propertiesof 404-di(ethynylphenyl)-20-nitro-1-benzenethiolate, which have been well known as a conducting molecule having possible applica-tion to molecular level negative dierential resistance (NDR) device. To deposit the self-assembly monolayers onto the gold elec-trode, we transfer the prefabricated Au(11) substrates into 0.5 mM self-assembly molecule in THF solution. Then, wemeasured electrical properties and surface morphologies 404-di(ethynylphenyl)-20-nitro-1-benzenethiolate using ultra-high vacuumscanning tunneling microscopy (UHV STM). Currentvoltage curves also showed several peaks between negative and positiveregion. KCI Citation Count: 5