Improved device performance of Si-based heterojunction solar cells by using phosphorus doped Si nanocrystals embedded in SiC host matrix

Phosphorus-doped Si nanocrystals embedded in amorphous SiC (Si NCs:SiC) films were fabricated by annealing phosphorus-doped Si-rich amorphous SiC materials at 900°C to get n-type Si NCs/p-Si heterojunction for photovoltaic device applications. The film compositions and the microstructure were characterized by X-ray photoelectron spectra and Raman scattering technique. After phosphorus doping, the dark conductivity can reach to be as high as 48 S/cm which is increased by six orders of magnitude compared with the un-doped one, while the bandgap keeps almost unchanged around 2.14 eV. The improved device performance was confirmed with the fill factor of 58% and the power conversion efficiency of 6.11%, which can be attributed to the good conductivity of phosphorus-doped Si NCs and the improved rectification characteristics of heterojunction structures.