Noise and Microwave Properties of Set-Transistors

Abstract

Electron tunneling through a small tunnel junction with capacitance C ₀ is suppressed by the so-called Coulomb blockade if the charging energy E _c = e ²/2C∑ is larger than the thermal energy k _B T 1. This effect is observed in a single electron tunneling transistor (SETT), which is a nano-meter size three-terminal device in which two leads connect to a small metallic island through two tunnel junctions. The excess charge on the island is regulated by the potential of the capacitively coupled gate electrode. The SETT is a very sensitive electrometer, noise levels of 10⁻⁵e/√Hz have been reached.2,3 A similar device, the electron pump, is made by connecting two or more islands in series through small tunnel junctions and varying the potential of each island in turn by gate electrodes. Pumps made this way can be very accurate, error rates of 10⁻⁸have been demonstrated.4