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Investigation of the thermal stability of MoOx as hole-selective contacts for Si solar cells.
- Source :
-
Journal of Applied Physics . 2018, Vol. 124 Issue 7, pN.PAG-N.PAG. 7p. 9 Graphs. - Publication Year :
- 2018
-
Abstract
- The stoichiometry and work function of molybdenum oxide (MoOx) are of crucial importance for its performance as hole selective contact for crystalline silicon solar cells. Hydrogenated amorphous silicon (a-Si:H) is typically used as an interface passivation layer in combination with MoOx to reduce surface recombination. As the fabrication process of a solar cell typically contains subsequent high-temperature processes, the consideration of thermal stability of MoOx with and without a-Si:H becomes critical. In this work, in situ x-ray spectroscopy (XPS)/ultraviolet photoelectron spectroscopy and Fourier transform infrared spectroscopy in the temperature range from 300 K to 900 K are used to investigate the thermal stability of MoOx with and without a-Si:H. In addition, both the passivation and contact performance are studied by evaluating the surface saturation current density J0s, carrier lifetime τeff, and contact resistivity ρc. The XPS results reveal that the as-evaporated MoOx on top of both c-Si and a-Si:H is sub-stoichiometric, and the work function of both films is higher than 6 eV. While after in situ annealing, the evolution of MoOx phase on top of a-Si:H shows a different behavior compared to it on c-Si which is attributed to H diffusion from a-Si:H after 600 K, whereas the work function shows a similar trend as a function of the annealing temperature. The J0s of a p-type Si symmetrically passivated by MoOx is found to be 187 fA/cm2 and the ρc is ∼82.5 mΩ·cm2 in the as-evaporated state. With a-Si interface passivation layer, J0s is significantly lower at 5.39 fA/cm2. The J0s and the ρc increase after post-deposition annealing. The evolution of these functional properties can be attributed to the material properties. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00218979
- Volume :
- 124
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- Journal of Applied Physics
- Publication Type :
- Academic Journal
- Accession number :
- 131363209
- Full Text :
- https://doi.org/10.1063/1.5041774