An On-Chip Break Junction System for Combined Single-Molecule Conductance and Raman Spectroscopies

Systems that are capable of robustly reproducing single-molecule junctions are an essential prerequisite for enabling the wide-spread testing of molecular electronic properties, the eventual application of molecular electronic devices, and the development of single-molecule based electrical and optical diagnostics. Here, a new approach is proposed for achieving a reliable single-molecule break junction system by using a microelectromechanical system device on a chip. It is demonstrated that the platform can (i) provide subnanometer mechanical resolution over a wide temperature range (approximate to 77-300 K), (ii) provide mechanical stability on par with scanning tunneling microscopy and mechanically controllable break junction systems, and (iii) operate in a variety of environmental conditions. Given these fundamental device performance properties, the electrical characteristics of two standard molecules (hexane-dithiol and biphenyl-dithiol) at the single-molecule level, and their stability in the junction at both room and cryogenic temperatures (approximate to 77 K) are studied. One of the possible distinctive applications of the system is demonstrated, i.e., observing real-time Raman scattering in a single-molecule junction. This approach may pave a way to achieving high-throughput electrical characterization of single-molecule devices and provide a reliable platform for the convenient characterization and practical application of single-molecule electronic systems in the future.