Thin Films & Nanostructures

Granular Electronic Systems

Granular electronic systems

Nano-Granular Metals

Our approach to granular electronic systems uses FEBID employing suitable precursor materials which directly result in deposits with nano-granular microstructure. In such disordered nano-granular metals electronic charge transport is highly correlated and results in a rich phase diagram of transport regimes where the inter-granular tunnel coupling strength g controls whether a sample is insulating or quasi-metallic. We also work on combining FEBID with atomic layer deposition (ALD) to fabricate ordered nano-granular metals.

Single electron transistor

Single Electronics

Another approach to fabricating granular electronic systems is by creating regular arrays of single nano-sized islands. As a first step we study the electronic transport properties of one individual nano-island as part of a single-electron transistor (SET) device. For island diameters of typically 20 - 30 nm the island's microstructure is itself nano-granular (grain diameter 2 - 3 nm) and the tunnel coupling between the grains can be finely tuned. The tunnel coupling of the island depends on its distance two the drain and source leads, as well as the embedding dielectric. At low temperatures (T < 10 K) periodic differential conductance oscillations (Bloch oscillations) occur as a function of the gate voltage.