Nonlinear 1/f noise characteristics in luminescent porous silicon

We present noise characteristics of luminescent porous silicon and show that they shed light on the transport mechanism in this system. The 1/f fluctuations show non-Gaussian and nonlinear behavior, and they give a high Hooge factor, typical of disordered conductors. By carrying out the measurements under various bias conditions, we found a bias-dependent redistribution of the percolating current paths. The close resemblance between the present results and those found in granular metals suggests that a tunneling process controlled by the electrostatic energy determines the conduction paths between the nanocrystallites in luminescent porous silicon.