Activated transport and scaling behavior in the current-voltage characteristics and Coulomb-blockade oscillations of two-dimensional arrays of metallic islands

We have investigated the transport properties of two-dimensional arrays of normal islands interconnected by tunnel junctions fabricated close to a conducting ground plane. For bias voltages V below a threshold voltage V-th, the current I is thermally activated with an activation energy proportional to V-th-V. For V>V-th, I scales as (V-V-th)(zeta), where zeta=2.01+/-0.04 and 1.58+/-0.04 for two samples. For constant V, I exhibits Coulomb-blockade oscillations as a function of the voltage of the ground plane. The amplitude of these oscillations scales as (V-V-th)(Chi), where Chi=0.68+/-0.18 and 0.31+/-1-0.10 for the same samples, respectively. These values are consistent with our theoretical prediction Chi=(zeta-1)/2.