Linewidths Of The Electronic Excitation-Spectra Of Donors In Silicon

The excitation spectra of phosphorus, arsenic, isolated interstitial lithium, and lithium oxygen donors in silicon have been investigated under the high resolution of a Fourier-transform spectrometer. Using a strain-free mounting technique, the linewidths are observed to be much narrower than those reported earlier in the literature; the observed linewidths appear to be limited by the lifetime effects. The linewidths and shapes of the excitation lines of phosphorus donors in silicon, introduced by the nuclear transmutation of $^{30}\\mathrm{Si}$ into $^{31}\\mathrm{P}$ by the capture of a slow neutron followed by a ${\\ensuremath{\\beta}}^{\\ensuremath{-}}$ decay, are studied; the influence of the charged defects produced by neutron irradiation is demonstrated and explained in terms of the electric fields due to charged impurities and defects.