Effect of heavy doping on the optical properties and the band structure of silicon

Abstract

We have measured by ellipsometry the dielectric constant of pure and heavily doped $n$- and $p$- type silicon from 1.8 to 5.6 eV. Both ion-implanted laser-annealed and bulk doped samples were used with concordant results. A red shift of the $E_1$ and $E_2$ critical-point energies, together with a decrease in the excitonic interaction at the $E_1$ energy, has been observed. These results are compared with first- and second-order perturbation-theory calculations of the effect of the impurities on the band structure of silicon.