We report photocarrier time-of-flight measurements in diode structures made of highly porous crystalline silicon. The corresponding electron and hole drift mobilities are very small ð<104 cm2=V sÞ compared to homogeneous crystalline silicon. The mobilities are dispersive (i.e., having a power-law decay with time or length-scale), but are only weakly temperature-dependent. The dispersion parameter lies in the range 0.55–0.65 for both electrons and holes. We conclude that the drift mobilities are limited by the nanoporous geometry, and not by disorder-induced localized states acting as traps. This conclusion is surprising in the context of luminescence models based on radiative recombination of localized excitons.
"Photocarrier Drift Mobility Measurements and Electron Localization in Nanoporous Silicon," P. N. Rao, E. A. Schiff, L. Tsybeskov, and P. Fauchet, Chemical Physics 284, 129-138 (2002).
harvested from author's c.v.