Influence of sample oxidation on the nature of optical luminescence from porous silicon

Site-selective luminescence experiments were performed upon porous-silicon samples exposed to varying degrees of oxidation. The source of different lu minescence bands was determined to be due to either quantum confinement in nanocrystalline silicon or defective silicon oxide. Of particular interest is the defective silicon-oxide luminescence band found at 2.1 eV, which was found to frequently overlap with a luminescence band from nanocrystalline silicon. Some of the historical confusion and debate with regards to the so urce of luminescence from porous silicon can be attributed to this overlap. (C) 2000 American Institute of Physics. [S0003-6951(00)01330-9].