  A multilayer edge molecular electronics device (MEMED), which utilize the two
metal electrodes of a metal-insulator-metal tunnel junction as the two
electrical leads to molecular channels, can overcome the long standing
fabrication challenges for developing futuristic molecular devices. However,
producing ultrathin insulator is the most challenging step in MEMED
fabrication. A simplified molecular device approach was developed by avoiding
the need of depositing a new materiel on the bottom electrode for growing
ultrathin insulator. This paper discuss the approach for MEMED's insulator
growth by one-step oxidation of a tantalum (Ta) bottom electrode, in the
pholithographically defined region; i.e. ultrathin tantalum oxide (TaOx)
insulator was grown by oxidizing bottom metal electrode itself. Organometallic
molecular clusters (OMCs) were bridged across 1-3 nm TaOx along the perimeter
of a tunnel junction to establish the highly efficient molecular conduction
channels. OMC transformed the asymmetric transport profile of TaOx based tunnel
junction into symmetric one. A TaOx based tunnel junction with top
ferromagnetic (NiFe) electrode exhibited the transient current suppression by
several orders. Further studies will be needed to strengthen the current
suppression phenomenon, and to realize the full potential of TaOx based
multilayer edge molecular spintronics devices.
