Resistive switching memories have gained an increased interest due to the possibilities for downscaling of memory devices down to a few nanometers. These memories consist of a resistive material... Show moreResistive switching memories have gained an increased interest due to the possibilities for downscaling of memory devices down to a few nanometers. These memories consist of a resistive material sandwiched between two metal electrodes, and applying a voltage between them induces resistance switching. In this thesis we study the specific case when switching is due to the reversible formation of a conductive path that connects and disconnects the electrodes. We investigate the electrical conductance properties and transport mechanisms in solid electrolyte memory devices, to gain a fundamental understanding of conductance switching. Our model system consists of Ag2S thin films with a Ag bottom electrode and a Pt AFM or STM tip as top electrode. We present a quantitative analysis of the steady state transport that leads up to resistance switching. We discuss the relation between stoichiometry and resistance changes in the material, and the necessity of Ag supersaturation prior to nucleation and switching. We also discuss the possible presence of two distinct switching mechanisms in Ag2S. Our findings could be extended to other semiconductor materials with mobile donors or acceptors. Show less
