Intrinsic noise of the single-electron transistor.

then the tunneling events become correlated. These correlations result in several remarkable features of the dc I-V curve. ' In particular, it is sensitive to fractional variations (in units of the electron charge e} of the background charge Qo of the central electrode (Fig. 2). One can control the current through the SET by variation of the charge Qo. Figure 1(b) shows an equivalent circuit of the SET coupled via the capacitance Co to a signal source (with finite internal capacitance C, ) generating the charge Q, . In the case of large internal internal capacitance, C, ))Co, it is possible to describe the The progress of modern nanotechnology allows the observation of several effects associated with charging of small tunnel structures by single electrons. ' These single-electron effects are of considerable interest not only because of their physics, but also because of the possibility to create various analog and digital "single-electron" devices. ' The most simple, but very promising, device is the socalled single-electron transistor (SET}. Its basic circuit consists of two small-area tunnel junctions connected in series and biased by a dc voltage source [Fig. 1(a)]. If the temperature T and the junction capacitances C& (j = 1,2 } are small enough,