On the effects of hydrogenation of thin film polycrystalline silicon: A key factor to improve heterojunction solar cells

The hydrogen plasma passivation of thin film polycrystalline silicon (pc-Si) was investigated in conjunction with plasma texturing process to make efficient heterojunction solar cells. The pc-Si layers were first treated using direct and remote hydrogen plasma technologies. The heterojunction solar...

Full description

Saved in:
Bibliographic Details
Published in:Solar energy materials and solar cells 2014-03, Vol.122, p.31-39
Main Authors: Qiu, Yu, Kunz, Oliver, Fejfar, Antonin, Ledinsky, Martin, Chan, Boon Teik, Gordon, Ivan, Van Gestel, Dries, Venkatachalm, Srisaran, Egan, Renate
Format: Article
Language:English
Subjects:
Diffusion
Heterojunctions
Hydrogen plasma
Hydrogenation
Photovoltaic cells
Platelets
Silicon
Solar cells
Thin films
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The hydrogen plasma passivation of thin film polycrystalline silicon (pc-Si) was investigated in conjunction with plasma texturing process to make efficient heterojunction solar cells. The pc-Si layers were first treated using direct and remote hydrogen plasma technologies. The heterojunction solar cells were then fabricated by subsequent deposition of i/n super(+) a-Si:H. Hydrogenation at high temperature (610 C) results in enhanced dissolution and diffusion of hydrogen in pc-Si by a factor of about 3 and 4, respectively, in comparison with those at low temperature (420 C). The hydrogen atoms in the pc-Si layer mainly bond to the silicon dangling bonds and form complexes with dopant atoms. In addition, platelets defects are generated by the hydrogen plasma in the sub-surface region of pc-Si hydrogenated at 420 C and cause higher saturation current in the space charge region whilst they form in the region deeper than 1 [mu]m at 610 C. Removal of the platelets using SF sub(6)/N sub(2)O plasma post-texturing after low-temperature hydrogenation not only enhances the short circuit current but also improves the open circuit voltage and the fill factor simultaneously. Combining plasma pre-texturing with high-temperature hydrogenation, the best 2 [mu]m-thick pc-Si heterojunction solar cell reaches an efficiency of 8.54%.
ISSN:0927-0248
DOI:10.1016/j.solmat.20l3.11.017