Applied Surface Science, Vol.416, 980-987, 2017
Correlation between the physical parameters of the i-nc-Si absorber layer grown by 27.12 MHz plasma with the nc-Si solar cell parameters
Growth of highly conducting nanocrystalline silicon (nc-Si) thin films of optimum crystalline volume fraction, involving dominant < 220 > crystallographic preferred orientation with simultaneous low fraction of microstructures at a low substrate temperature and high growth rate, is a challenging task for its promising utilization in nc-Si solar cells. Utilizing enhanced electron density and superior ion flux densities of the high frequency (similar to 27.12 MHz) SiH4 plasma, improved nc-Si films have been produced by simple optimization of H-2-dilution, controlling the ion damage and enhancing supply of atomic-hydrogen onto the growing surface. Single junction nc-Si p-i-n solar cells have been prepared with i-nc-Si absorber layer and optimized. The physical parameters of the absorber layer have been systematically correlated to variations of the solar cell parameters. The preferred < 220 > alignment of crystallites, its contribution to the low recombination losses for conduction of charge carriers along the vertical direction, its spectroscopic correlation with the dominant growth of ultra-nanocrystalline silicon (unc-Si) component and corresponding longer wavelength absorption, especially in the neighborhood of i/n-interface region recognize scientific and technological key issues that pave the ground for imminent advancement of multi-junction silicon solar cells. (C) 2017 Elsevier B.V. All rights reserved.