Microscope of glassy relaxation in femtogram samples: Charge offset drift in the single electron transistor

By measuring the long-term charge offset drift in single electron tunneling transistors, we have observed a transient relaxation after fabrication which is correlated with the presence of amorphous insulator. The temperature and time dependence of the transient relaxation are both in agreement with an extension of the standard model for two-level systems in glasses. This technique, which is sensitive to atomic scale motion in femtogram-sized samples, offers the possibility of a technique for investigation of glassy relaxation.