Molecular Tunnel Junctions : Metal / OML – Si(111)

Understanding the electronic properties of tunnel junctions which incorporate a nanometer-thick organic insulator remains a fundamental issue for molecular electronics. Covalent grafting of a densely-packed monolayer of n-alkyl saturated chains to Si(111) surfaces provides MIS tunnel junctions (metal / OML / semiconductor) which can be easily tuned : n or p doping of Si, insulating chain length and coverage, chemical functionality of the chains at the top metal interface.
Electronic properties of MIS tunnel junctions Hg // OML - Si (111) were characterized in static (current-voltage) and dynamic (admittance) modes. The interpretation of transport mechanisms and dipolar relaxation relies on modeling the characteristics measured as a function of temperature and applied voltage. Dynamic studies of defects and disorder of molecular chains grafted to crystalline Si surfaces are analyzed with multiscale models.