EXPERIMENTAL AND THEORETICAL ASPECTS OF RADIATIVE PROCESSES IN POROUSSILICON

We have measured the temperature dependence of the radiative lifetime between 4 and 300 K. This dependence is interpreted as due to the exch ange splitting E(ex) = 10 meV of an electron-hole pair confined in a s ilicon crystaIlite for a luminescence wavelength equal to 0.7 mu m. Th en we present a variational calculation taking into account the correl ation of the electron-hole pair due to the Coulomb interaction. This l eads us to conclude that the measured exchange splitting corresponds t o a (spherical)crystallite of diameter 32 Angstrom.