Surface potential mapping of patterned self-assembled monolayers by scanning probe microscopy

Surface potentials of a number of patterned conducting and insulating self-assembled monolayers (SAMs) were measured by scanning surface potential microscopy (SSPM) as part of a study in molecular electronics. Differences in surface potential were measured for insulating and conducting molecule SAMs on gold. The SAMs were patterned by microcontact printing. High contrast patterns were observed by surface potential even when little imaging was possible in standard AFM modes. Surface potential differences of a few mV to 500 mV were observed under ambient conditions between adjacent SAMs of different compositions or between SAMs and the unmodified substrate.