THE RADIOFREQUENCY SINGLE-ELECTRON TRANSISTOR (RF-SET) - A FAST AND ULTRASENSITIVE ELECTROMETER

A new type of electrometer is described that uses a single-electron tr ansistor (SET) and that allows large operating speeds and extremely hi gh charge sensitivity. The SET readout was accomplished by measuring t he damping of a 1.7-gigahertz resonant circuit in which the device is embedded, and in some ways is the electrostatic ''dual'' of the well-k nown radio-frequency superconducting quantum interference device. The device is more than two orders of magnitude faster than previous singl e-electron devices, with a constant gain from de to greater than 100 m egahertz. For a still-unoptimized device, a charge sensitivity of 1.2 x 10(-5) e/root hertz was obtained at a frequency of 1.1 megahertz, wh ich is about an order of magnitude better than a typical, 1/f-noise-li mited SET,and corresponds to an energy sensitivity (in joules per hert z) of about 41 (h) over bar.