ROOM-TEMPERATURE SINGLE-ELECTRON JUNCTION

The design, realization, and test performances of an electronic juncti on based on single-electron phenomena that works in the air at room te mperature are hereby reported, The element consists of an electrochemi cally etched sharp tungsten stylus over whose tip a nanometer-size cry stal was synthesized, Langmuir-Blodgett films of cadmium arachidate we re transferred onto the stylus and exposed to a H2S atmosphere to yiel d CdS nanocrystals (30-50 Angstrom in diameter) imbedded into an organ ic matrix. The stylus, biased with respect to a flat electrode, was br ought to the tunnel distance from the film and a constant gap value wa s maintained by a piezo-electric actuator driven by a feedback circuit fed by the tunneling current. With this set-up, it is possible to mea sure the behavior of the current flowing through the quantum dot when a bias voltage is applied. Voltage-current characteristics measured in the system displayed single-electron trends such as a Coulomb blockad e and Coulomb staircase and revealed capacitance values as small as 10 (-19) F.