  Nonradiative exciton lifetime in silicon is determined by comparison of the
experimental and theoretical curves of bulk minority charge carriers lifetime
on doping and excitation levels. This value is used to analyze the influence of
excitonic effects on internal luminescence quantum yield at room temperature,
taking into account both nonradiative and radiative exciton lifetimes. A range
of Shockley-Hall-Reed lifetimes is found, where excitonic effects lead to an
increase of internal luminescence quantum yield.
