EFFECT OF SURFACE-TREATMENT ON VISIBLE LUMINESCENCE OF POROUS SILICON - CORRELATION WITH HYDROGEN AND OXYGEN TERMINATORS

The effect of hydrogen and oxygen surface termination atoms on the visible luminescence of porous Si was investigated for underlying physical mechanism. Atmospheric thermal treatment up to 1000-degrees-C was carried out to study the functional relationship between the surface coverage and photoluminescence (PL). The results show that oxygen incorporation induces surface modification that enhance the PL efficiency after the removal of all SiH(x) (x = 1-3) species. The presence of oxygen atoms can also account for the observed PL redshift along with the usual blueshift. The molecular orbital calculations on the cluster modeling showed the significance of oxygen atoms in modifying the electronic structure of porous Si.