Observation of Quantized Ballistic Transport in Amorphous Silicon Memory Structures

Abstract

ABSTRACTWe present experimental results showing that the ON state of amorphous silicon memory structures exhibits ballistic electron transport associated with a quantised resistance, h/2ie2, where i is the number of occupied one dimensional conducting channels (sub-bands) and the spin degeneracy is two (in the case when no magnetic field is applied). Conduction in the memory ON state is restricted to a narrow conducting channel through which the electrons can travel ballistically i.e. no collisions occur. As the applied voltage is increased, the width of the conducting channel is broadened. This results in additional conducting channels (sub-bands) passing through the Fermi energy and consequently the resistance drops by quantised values. In the presence of a magnetic field additional steps occur corresponding to the split levels at values of h/2(i + ½)e2. A particular feature of this quantised resistance is that the effect can be observed at relatively high temperatures effect can be observed at relatively high temperatures (from 4.2 K up to ∼190K).