Single electron transistor with two gate inputs

We fabricate a single electron tunneling (SET) transister, and add an extra electrode covering the whole surface. This extra electrode works well as another gate input with the effective gate capacitance of 2 aF, which is 1/80 of that of the on-chip gate (0.16 fF). Compared with the noises under the operation by the two gate input, it is found that the SET transistor with the extra gate operation becomes noisy more than one order of magnitude of that with the on-chip gate.