Conduction Mechanism Switching from Coulomb Blockade to Classical Critical Percolation Behavior in Disordered Nanoparticle Array

Large, open-gate transistors made from metal nanoparticle arrays offer possibilities to build new electronic devices, such as sensors. A nanoparticle necklace network (N³) of Au particles from 300 K to cryogenic temperatures exhibit a nonohmic I–V_d behavior, I ≈ (V_d–V_T)^ζ, where V_T is a conduction gap and ζ is a constant critical exponent. The conduction gap in N³, made from disordered networks of 1D chains of 10 nm diameter Au particles exhibits room temperature (RT) gating. Although the I–V_d behavior at RT is identical to Coulomb blockade, the conduction is modulated by field-assisted tunneling exhibiting classical critical behavior. In this study, based on three results, invariance of V_T on gating, invariance of V_T on temperature, and zero–bias conductance, a sharp transition temperature at ≈140 K is discovered where the conduction mechanism switches from Coulomb blockade to classical critical percolation behavior. The N³ architecture allows the reconciliation of the Coulomb blockade versus activation process as a sharp thermal transition to serve as a model system to study the exotic behavior in nanogranular-metallic materials. The novel global critical behavior to local Coulomb blockade governed transition in these N³ architectures may potentially lead to novel sensors and biosensors.