Line shape of the no-phonon luminescence of excitons bound to phosphorus in carbon-doped silicon.

Isoelectronic substitutional carbon atoms, present as an impurity in crystalline silicon, are shown to split the no-phonon luminescence line produced by the decay of excitons bound to phosphorus donors. The centroid of the doublet moves to lower photon energy in proportion to the carbon concentration. The splitting and shift can be explained quantitatively as a perturbation of the transition by the strain produced by the carbon. \textcopyright{} 1996 The American Physical Society.