Investigation of the offset charge noise in single electron tunneling devices

The offset charge noise in metallic single electron tunneling (SET) devices fabricated on dielectric substrates was experimentally studied. On the basis of stereoscopic measurements of the low-frequency charge noise we show that the substrate makes an essential contribution to the total noise. We have observed that the intensity of the charge noise in SET transistors depends on the biasing dc current but is almost insensitive to temperature variations up to 300 mK. Stability investigations of an SET trap gave storage times of more than 8 h. The performance of such a device is affected by the bias current of a readout electrometer, located nearby, and by background charges.