Interpretation of photoluminescence excitation spectroscopy of porous Si layers

Abstract

Photoluminescence excitation (PLE) measurements allow one to obtain direct information on the absorption processes in porous Si leading to the strong visible luminescence which has recently been reported. This technique does not need a free-standing porous Si sample, but the effect of layer thickness should be included in the interpretation of PLE data. In our PLE spectra, two separate absorption edges are observed and the initial one shifts to higher energies with storage time. The trends of these changes are consistent with the quantum wire model.