The photoluminescence of porous silicon in the temperature range from
300 to 400 K is investigated. It is shown that the experimental result
s are explained well on the basis of a model of the radiative recombin
ation of excitons in silicon nanostructures. According to numerical es
timates obtained by comparing the experimental and calculated curves,
the exciton binding energy is 0.2 eV. (C) 1997 American Institute of P
hysics.