• V. S. Waman
• M. M. Kamble
• S. W. Gosavi
• S. R. Jadkar

Demand for an efficient intrinsic layer for a-Si:H based solar cells in terms of microstructure is ever increasing since the inception of single junction and tandem solar cells. In this paper, we report synthesis of high quality hydrogenated protocrystalline silicon (pc-Si:H) thin films by HW-CVD using the mixture of silane (SiH4) and hydrogen (H2). Variation in film characteristics with filament-to-substrate distance (ds-f) was studied, and revealed that the structural changes occur in film structure. The filament-to-substrate distance was varied in between 6 cm - 10 cm. The structural properties were studied by Raman and FTIR spectroscopy. Raman spectroscopy results shows with decrease in filament-to-substrate distance the structural changes occurs in thin films. The bond angle variation (b) of the films is in between 7.34 - 8.43 degrees. Fourier transform infrared spectroscopic analysis showed that the hydrogen mainly bonded with monohydride (Si-H) bonding configuration in all the films deposited at different filament-to-substrate distance. The hydrogen content (CH) in the films increases with increasing filament-to-substrate distance and was found to be  10.5 at. % over the entire range of filament-to-substrate distance studied. The microstructure parameter (R*) was found to be decreases 0.19 - 0.16 for the films deposited at higher filament-to-substrate distance and increases upto 0.43 at lower filament-to-substrate distance. The low value of microstructure parameter (R*) at ds-f = 8 cm, suggesting that there is an enhancement of structural order and homogeneity in the film also revealed by Raman spectroscopy. The results obtained by FTIR and Raman suggests that the films deposited at the onset of nanocrystallization i. e. at ds-f = 8 cm called protocrystalline nature of the film. From the present study it has been concluded that the filament-to-substrate distance is a key process parameter to decrease structural disorder in thin films deposited by HW-CVD. The obtained film can be use as an intrinsic layer in p-i-n solar cell and Tandem solar cell.

Hot wire chemical vapor deposition, Hydrogenated protocrystalline silicon, FTIR spectroscopy, Raman spectroscopy, Microstructural properties.

"EVOLUTION OF MICROSTRUCTURAL PROPERTIES OF HYDROGENATED PROTOCRYSTALLINE SILICON (PC-SI:H) THIN FILMS DEPOSITED BY HW-CVD", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 5, page no.65-69, MAY-2019, Available :http://www.jetir.org/papers/JETIRCM06018.pdf

"EVOLUTION OF MICROSTRUCTURAL PROPERTIES OF HYDROGENATED PROTOCRYSTALLINE SILICON (PC-SI:H) THIN FILMS DEPOSITED BY HW-CVD", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 5, page no. pp65-69, MAY-2019, Available at : http://www.jetir.org/papers/JETIRCM06018.pdf