Light-emitting mechanism conversion in C 60-coupled porous Si systems

Abstract

We reveal two kinds of light-emitting origins in two typical porous Si (PS) samples by carefully examining the photoluminescence (PL) and PL excitation (PLE) spectra. The interfacial oxygen-related defect states and SiO binding states at the surfaces of the two samples are considered to be responsible for the two emissions, which is useful in clarifying some problems in controversy related to the emission mechanisms of PS. After the two kinds of PS samples were coupled with C 60 molecules, the PL from the surface states is replaced by the emission associated with the oxygen-related defects. The coupling process plays an important role in conversion of the light-emitting mechanism. We suggest that this PL conversion is due to destruction of original SiO binding states caused by C 60 coupling and therefore the PL from the interfacial defect states becomes main emission process.