Transport study of self-supporting porous silicon

Abstract

We have measured dark DC conductivity and time-of-flight (TOF) of carriers in self-supporting porous silicon films in the temperature range 298–480 K. The dark I-V curves show superlinear behavior with activation energies of 0.38–0.67 eV. The TOF measurements allowed us to evaluate the drift-length of non-equilibrium carriers and revealed a significant decrease of the collected charge with increasing delay (tdel≥1 ms) of the exciting 3 ns laser pulse after the voltage application, probably due to field redistribution in the Si crystallites.