Investigation on the effects of phosphine doping in Si nanocrystal material

The behavior of phosphine-doped Si nanocrystal material is studied in this work from the perspectives of crystallization, photoluminescence, carrier density and conductivity. Phosphine was incorporated in the material during the sputter process. It was observed that the phosphine helped to reduce the defects in the material. This was evident from the reduction of the photoluminescence of a possible defect-related energy level located at 1.30 eV, which prevailed at low temperature when phosphine was absent. Temperature dependent Hall measurement showed the carrier densities in Si nanocrystal material remained around 10¹⁹ and 10²⁰ cm^-3 from 80 K to 340 K for samples doped with 3 sccm and 9 sccm phosphine respectively during sputtering. Such metallic behavior can be due to degenerate doping in the material.