Absence of scaling in transport through two-dimensional nanoparticle arrays

We analyze the transport in disordered two-dimensional nanoparticle arrays. We show that the commonly used scaling hypothesis to fit the I-V curves does not describe the electronic transport in these systems. On the contrary, close to the threshold voltage V_T the current depends linearly on (V-V_T). This linear behavior is observed for at least five decades in (V-V_T). Fitting the I-V curves at larger voltages to a scaling power-law I \propto (V/V_T-1)^\xi results in fitting parameters which depend on the range of voltages used and in wrong values for V_T. Our results urge to change the picture of electronic transport in disordered nanoparticle arrays used in the last two decades.