Electron transport in silicon nanostructures based on ultra-thin SOI

We present an experimental study of ultra-thin SOI-based nanostructures. The systems have a van der Pauw geometry, with a radius of 2mum. The resistance per square R is first analyzed in the temperature range 300 K - 4.2 K, and for different conditions of back gate voltages (0 V< V-g < 4 V). The magnetoresistance was measured at very low temperatures (10 mK < T< 900 mK). for magnetic fields -2500 G< B < 2500 G. The experimental results exhibit a negative magnetoresistance that we attribute to quantum interference effects due to time reversed electron paths and known as weak localization. Fundamental properties of the material at low temperatures such as the electron phase coherence length to the elastic mean free path l(phi) and the mobility mu are then estimated throughout the obtained results.