Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

Ali, Haider; Yang, Xinbo; Weber, Klaus; Schoenfeld, Winston V.; Davis, Kristopher O.

Type

Article

Authors

Ali, Haider
Yang, Xinbo
Weber, Klaus
Schoenfeld, Winston V.
Davis, Kristopher O.

KAUST Department

KAUST Solar Center (KSC)

Date

2017-08-15

Metadata

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Abstract

In this study, the cross-section of electron-selective titanium oxide (TiO2) contacts for n-type crystalline silicon solar cells were investigated by transmission electron microscopy. It was revealed that the excellent cell efficiency of 21.6% obtained on n-type cells, featuring SiO2/TiO2/Al rear contacts and after forming gas annealing (FGA) at 350°C, is due to strong surface passivation of SiO2/TiO2 stack as well as low contact resistivity at the Si/SiO2/TiO2 heterojunction. This can be attributed to the transformation of amorphous TiO2 to a conducting TiO2-x phase. Conversely, the low efficiency (9.8%) obtained on cells featuring an a-Si:H/TiO2/Al rear contact is due to severe degradation of passivation of the a-Si:H upon FGA.

Citation

Ali H, Yang X, Weber K, Schoenfeld WV, Davis KO (2017) Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells. Microscopy and Microanalysis 23: 900–904. Available: http://dx.doi.org/10.1017/S1431927617012417.

Sponsors

The authors would like to thank Eric Schneller for assistance with analysis of the quantum efficiency and reflectance data. The authors acknowledge financial support from the Australian Renewable Energy Agency (ARENA) under the Postdoctoral Fellowship. The authors would also like to acknowledge support for this work by the US Department of Energy, Office of Energy Efficiency and Renewable Energy, in the Solar Energy Technologies Program, under Award Number DE-EE0004947. Finally, the Materials Characterization Facility at University of Central Florida (UCF) is acknowledged for usage of its facilities.

Publisher

Cambridge University Press (CUP)

Journal

Microscopy and Microanalysis

ISSN

1431-9276
1435-8115