Highly conducting phosphorous doped n-type nc-Si:H films by HW-CVD for c-Si heterojunction solar cells

作者：Waman Vaishali S^*; Kamble Mahesh M; Ghosh Sanjay S; Mayabadi Azam; Sathe Vasant G; Pathan Habib M; Shinde Shashikant D; Adhi Kiran P; Jadkar Sandesh R

来源：RSC Advances, 2012, 2(26): 9873-9880.

DOI：10.1039/c2ra21618c

Phosphorous doped hydrogenated nanocrystalline silicon (nc-Si:H) films were prepared using the hot wire chemical vapor deposition (HW-CVD) method at a low substrate temperature of 200 degrees C. The microstructure and opto-electrical properties of these films were systematically studied using Raman spectroscopy, low angle XRD, high resolution transmission electron microscopy (HR-TEM), UV-Visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, dark conductivity and its activation energy measurements and Hall measurement as a function of PH3 gas-phase ratio. It has been found that with an increase in the PH3 gas-phase ratio, both the volume fraction of the crystallites and its size decrease, signifying that the phosphorous atom favors the growth of amorphization in the nanocrystalline Si network. At the optimized PH3 gas-phase ratio we have obtained n-type nc-Si:H films with a band gap of similar to 1.84 eV, high dark conductivity (similar to 6.78 S cm(-1)) with low hydrogen content (similar to 1.72 at. %), at a reasonably high deposition rate (similar to 10 angstrom s(-1)). Finally, Al/ZnO:Al/n-nc-Si:H/buffer a-Si:H/p-c-Si/Al heterojunction solar cells were fabricated using the optimized n-layer, showing excellent photovoltaic performance with V-OC = 719 mV, J(SC) = 9.94 mA cm(-2), FF = 53.8%, and an energy conversion efficiency of 5.2%. These are very encouraging results for the future fabrication of high efficiency silicon heterojunction solar cells and thin film tandem solar cells.

• 出版日期2012