FINITE-FREQUENCY SHOT-NOISE IN A SINGLE-ELECTRON TRANSISTOR

Our previous work on finite-frequency shot noise S(omega) in a correla ted tunneling current has been extended to investigate the shot-noise behavior in a single-electron transistor (SET), with emphasis on asymm etric SET. We found that both the increase of the asymmetry and the in crease of the gate voltage will broaden S(omega), and S(0) is further suppressed by the gate capacitance. At low bias voltage, a condition i s obtained under which the noise spectrum S(omega) is white (frequency independent). We have also demonstrated at the quantitative level how the signal-to-noise ratio in a SET can be controlled by adjusting the gate voltage and the degree of asymmetry.