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Metallic single-electron transistor without traditional tunnel barriersa Lomonosov Moscow State University, Faculty of Physics, Laboratory of Cryoelectronics, Vorob'evy Gory, Moscow, 119992, Russia , Moscow , Russia b Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Leninskie Gory 1 build. 2, Moscow, 119991, Russian Federation c Physikalisch-Technische Bundesanstalt, Braunschweig, Germany We report a new type of single-electron transistor (SET) comprising two highly resistive Cr thin-film strips (∼1 μm long) connecting a 1μm-long Al island to two Al outer electrodes. These resistors replace small-area oxide tunnel junctions of traditional SETs. Our transistor with a total asymptotic resistance of 110 kΩ showed a very sharp Coulomb blockade and reproducible, deep and strictly eperiodic gate modulation in wide ranges of bias currents I and gate voltages Vg. In the Coulomb blockade region (|V|⩽ about 0.5 mV), we observed a strong suppression of the co-tunneling current allowing appreciable modulation curves V(Vg) to be measured at currents I as low as 100 fA. The noise figure of our SET was found to be similar to that of typical Al/AlOx/Al single-electron transistors, viz. δQ≈5×10−4e/√Hz at 10 Hz.
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