With the help of two single-electron tunneling transistors whose islands were positioned about 100 nm apart, a low-frequency charge noise generated in the ${\mathrm{Al}}_2$${\mathrm{O}}_3$ substrate has been measured. The signals detected by these electrometers have shown a 10–20 % correlation in power in the 1–10-Hz range. Using a simple model we show that the charge noise sources (fluctuating traps) can be distributed either in thin dielectric layers (including the barriers) adjacent to the islands or, alternatively but more likely, in a volume of the substrate. © 1996 The American Physical Society.

• Received 11 October 1995

DOI:https://doi.org/10.1103/PhysRevB.53.13682