NONRADIATIVE RECOMBINATION ON DANGLING BONDS IN SILICON CRYSTALLITES

The recombination of an electron-hole pair at a silicon dangling bond located on the surface of a silicon crystallite is studied. We find th at it is highly dependent on confinement. We show that the capture of an electron or a hole by a neutral dangling bond is a nonradiative pro cess in crystallites with bandgaps smaller than 2.2 eV. On the contrar y, the capture by a charged dangling bond is radiative. Therefore the presence of one dangling bond in a crystallite kills its luminescent p roperties above 1.1 eV but can produce a luminescence below 1.1 eV. Th e origin of the infrared luminescence of porous silicon is discussed i n light of these results.