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Resistance fluctations in submicrometer narrow Si inversion layers are studied over a wide range of temperatures and electron concentrations. Thermally activated switching on and off of discrete resistance increments is observed, caused by the capture and emission of individual electrons at strategically located scatterers (interface traps). The traps have a broad distribution of activation energies, as assumed in accounting for $\frac{1}{f}$ noise in larger devices.

The conductance of narrow (0.1-\ensuremath{\mu}m) silicon inversion layers has been measured at low temperatures. A divergent, nonmetallic decrease of conductance is observed below 30 K, in excellent quantitative agreement with the combined theories of weak localization and interaction effects in their one-dimensional form, if one assumes parameters comparable to those observed in wide (two-dimensional) inversion layers. In this novel experimental system both localization and interaction effects are present and comparable in size.

We have measured the distribution in current for the onset of voltage in small-area Josephson junctions for temperatures down to approx.1.6 K. The lifetime of the = 0 state for our highest current density junctions becomes temperature independent for k/sub B/T< or approx. =hw/sub 0//20, a T much less than the WKB prediction (w/sub 0/ is the junction resonant frequency). This is consistent with the Caldeira-Leggett theory, which includes damping effects on the quantum tunneling rate.