Radio-frequency single-electron transistor: Toward the shot-noise limit

We have fabricated an aluminum single-electron transistor and characterized it at frequencies up to 10 MHz by measuring the reflected signal from a resonant tank in which the transistor is embedded. We measured the charge sensitivity of this radio-frequency single-electron transistor to be 3.2×10−6 e/Hz, which corresponds to the uncoupled energy sensitivity of 4.8 ℏ. Our measurements indicate that with further improvements, the radio-frequency single-electron transistor could reach the shot-noise limit estimated to be about 1 ℏ.