Photoluminescence in the Earliest Stages of Porous Silicon Formation

The surface topography of (100) p‐Si surfaces at the early stages of electrochemical etching is examined and correlated with the visible photoluminescence (PL) normally observed from porous silicon. The results from three electrolytes are compared. PL is observed from the silicon with etch times as short as 10 s, well before pores are formed in the silicon. The topographical changes in the silicon surface are consistent with the formation of emitting, constrained surface species (oxyhydrides), however, nanometer size structures are also present which may be associated with the potential for quantum confinement.