Improvement of amorphous silicon n-i-p solar cells by incorporating double-layer hydrogenated nanocrystalline silicon structure

• Published in: Journal of non-crystalline solids Vol. 357; no. 1; pp. 121 - 125
• Main Authors: Liu, Shiyong, Zeng, Xiangbo, Peng, Wenbo, Xiao, Haibo, Yao, Wenjie, Xie, Xiaobing, Wang, Chao, Wang, Zhanguo
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 2011; Elsevier
• Subjects: Amorphous silicon; Applied sciences; Buffer layer; Buffer layers; Density; Dilution; Energy; Exact sciences and technology; Hydrogen storage; Hydrogenated nanocrystalline silicon; i/p interface; Nanocrystals; Natural energy; Photovoltaic cells; Photovoltaic conversion; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Thin films; Buffer layer; Solar cells; Hydrogenated nanocrystalline silicon; i/p interface; Defect states; Grain size; Defect density; Band structure; Interface electron state; Solar cell; Transmission electron microscopy; Amorphous hydrogenated material; Silicon; Wide band gap semiconductors; Activation energy; Raman spectrum; Double layers; Nanocrystal; Voltage capacity curve
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2010.10.001

We develop a double-layer p-type hydrogenated nanocrystalline silicon (p-nc-Si:H) structure consisting of a low hydrogen diluted i/p buffer layer and a high hydrogen diluted p-layer to improve the hydrogenated amorphous silicon (a-Si:H) n-i-p solar cells. The electrical, optical and structural properties of p-nc-Si:H films with different hydrogen dilution ratio ( R H) are investigated. High conductivity, low activation energy and wide band gap are achieved for the thin films. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) analyses indicate that the thin films contain nanocrystallites with grain size around 3–5 nm embedded in the amorphous silicon matrix. By inserting a p-nc-Si:H buffer layer at the i/p interface, the overall performance of the solar cell is improved significantly compared to the bufferless cell. The improvement is correlated with the reduction of the density of defect states at the i/p interface. ►We develop a double-layer p-nc-Si:H structure to improve the a-Si:H solar cell for the first time. ►The nc-Si:H buffer layer improves the Voc and the short wavelength response.