Microstructure Study of Photoluminescent Porous Silicon

We have studied the microstructure and photoluminescent properties of porous Si. High resolution observations revealed that the microstructure of porous Si consists with nano-crystallites Si embedded in the surrounding amorphous matrix. The structure of nano-crystallites of porous Si is not consistent with the usual diamond structure of bulk Si. The photoluminescence from porous Si is due to the quantum confinement of carriers in this structure.