Charge carrier transport in Si/CaF2 heterostructures controlled by formingbias

Electrical properties of structures consisting of CaF2 and Si nanosize laye rs have been investigated. Then is a strong asymmetry between forward and r everse current curves, as well as a shift of the voltage at which the curre nt is null. It has been found that after some electrical forming of the str uctures the current exhibits a well resolved non-monotonous N-type behavior at reverse bias conditions. The corresponding region of negative different ial resistance appears only once a forward bias has been applied. An attemp t is made to interpret the observed effect in terms of capturing of the car riers within the structure and their subsequent release through the structu re via tunneling.