Regensburg 1998 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Tiefe Temperaturen
TT 10: Postersitzung I: Ladungseffekte in Einelektronensystemen (1-6), Niedrigdimensionale Systeme (7-17), Transporteigenschaften und Pinning in HTSL (18-30), Symmetrie des Ordnungsparameters in HTSL (31-36), Korrelierte Elektronen: Theorie (37-79)
TT 10.4: Poster
Dienstag, 24. März 1998, 09:30–13:00, A
Coulomb blockade and Single Electron effects in arrays of selforganized ultrasmall metal clusters observed at room temperature — •Franz Kreupl1,2, Johann Vancea1, Lothar Risch2, and Horst Hoffmann1 — 1University of Regensburg, D-93040 Regensburg, Germany — 2Siemens AG, ZT ME 1, D-81739 Munich, Germany
In a first part we report on STM-studies of selforganized Pt clusters (1-4 nm in diameter) on top of a thin isolating Al2O3 layer being supported by an underlying atomically flat Au-substrate. The complete sample structure has been fabricated and measured in UHV without breaking the vacuum. With the STM-tip as a second contact electrode, this system establishes a double-tunnel-junction, which exhibits Coulomb blockade effects at room temperature. The recorded I(U)-curves on individual clusters showed a variety of features like a Coulomb gap, Coulomb staircase, barrier suppression and asymmetric tunneling barrier effects, with the Coulomb gap (0.3-1.5 eV) being the most often observed feature. In a second part we present the results of measurements done on an 2-dimensional array of selforganized Pt dots being placed in a 30-120 nm wide gap between two microstructured electrodes on top of an oxidized Si-wafer (100 nm SiO2). We demonstrated a clear Coulomb gap of 0.1 - 1 eV at room temperature. We were able to change the current through the array by applying a gate voltage to the silicon substrate and therefore demonstrated a transistor like device based on the single electron tunneling in a 2-dimensional array of selforganized metal dots.