Observation of double percolation transitions in Ag-SnO${}_2$ nanogranular films

Abstract

Two percolation transitions are observed in Ag${}_x$(SnO${}_2{)}_{1-x}$ nanogranular films with Ag volume fraction $x$ ranging from $\sim$0.2 to $\sim$0.9. In the vicinity of each percolation threshold $x_{ci}$ ($i$$=$1, 2), the variation in $\sigma$ with $x$ obeys a power law for $x$$>$$x_{ci}$. The origin of the first percolation transition at $x_{c1}$ ($x_{c1}$$>$$x_{c2}$) is similar to that of the classical one, while the second transition is explained as originating from the tunneling to the second-nearest neighboring Ag particles. These observations provide strong experimental support for the validity of current theories concerning tunneling effect in conductor-insulator nanogranular composites.

4 pages and 4 figures

References in corpus (2)

• Tunneling and Non-Universality in Continuum Percolation Systems
• Percolation-to-hopping crossover in conductor-insulator composites

Cited by in corpus (3)

• Theory of percolation and tunneling regimes in nanogranular metal films
• Dimensional effects on the tunneling conductivity of gold-implanted nanocomposite films
• Crossover From Cooper-Pair Hopping to Single-Electron Hopping in Pb${}_x$(TiO${}_2$)${}_{1-x}$ Granular Films