High-Performance TiO2-Based Electron-Selective Contacts for Crystalline Silicon Solar Cells

Xinbo Yang*, Qunyu Bi, Haider Ali, Kristopher Davis, Winston V. Schoenfeld, Klaus Weber

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

211 Scopus citations

Abstract

A high-quality, low-cost TiO2 -based electron-selective contact for silicon solar cells was developed. Thin TiO2 films were deposited by ALD with the titanium chloride titanium precursor and H2O oxidant at a low temperature of 75°C, and N2 was used as the purge gas. To investigate the surface passivation quality of thin TiO2 on silicon surfaces, symmetrical test structures were fabricated on (100)-oriented n-type and p-type silicon wafers to allow injection-dependent lifetime measurement utilizing the quasi-steady state Photoconductance (QSSPC) technique. The wafers were chemical-polished and RCA cleaned followed by a short dip in diluted HF before TiO2 film deposition. TiO2 film thicknesses were determined from ellipsometry measurement by fitting polarized reflectance data of single side polished silicon wafers. The implementation of the TiO2 -based contacts reduces the surface recombination and contact resistivity at the silicon and metal interface simultaneously, resulting in a higher V oc and FF for silicon solar cells. The champion efficiency of 21.6% has been achieved on the n-type silicon solar cell featuring a full-area TiO2 -based contact.

Original languageEnglish (US)
Pages (from-to)5891-5897
Number of pages7
JournalAdvanced Materials
Volume28
Issue number28
DOIs
StatePublished - Jan 1 2016

Keywords

  • carrier-selective contacts
  • heterojunctions
  • solar cells
  • titanium dioxide

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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