Exploring hafnium oxide's potential for passivating contacts for silicon solar cells

Abstract: We investigate the potential of ultra-thin HfO2 films grown by atomic layer deposition for passivating contacts to silicon focusing on variations in film thickness and post-deposition annealing temperature. A peak in passivation quality – as assessed by carrier lifetime measurements – is reported for 2.2 nm thick films annealed at 475 °C, for which a surface recombination velocity <1 cm/s is determined. For films <2.2 nm thick, there is a marked decrease in passivation quality. X-ray diffraction highlights a change from crystallised monoclinic to amorphous HfO2 as film thickness decreases from 12 nm to 2.2 nm. Kelvin probe results indicate that as-deposited 2.2–12 nm films have similar effective work functions, although the work function of 1 nm films is considerably lower. Upon post-deposition annealing in vacuum, all films exhibit a reduction in effective work function at temperatures coincident with the onset of passivation in air-annealed samples. An initial investigation into the contact resistivity in a passivating contact structure utilizing HfO2 reveals a strong post-deposition annealing temperature dependence, with the lowest resistance achieved below 375 °C, followed by a decrease in performance as temperature increases towards the optimal temperature for passivation (475 °C). Limitations of the contact structure used are discussed

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: Solar energy materials & solar cells. - 259 (2023) , 112457, ISSN: 1879-3398

Classification and Topics

• Classification: Elektrotechnik, Elektronik

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2024
• Creator: Wratten, Ailish ; Pain, Sophie L. ; Yadav, Anup ; Khorani, Edris ; Niewelt, Tim ; Black, Lachlan E. ; Bartholazzi, Gabriel ; Walker, David Johannes ; Grant, N.E ; Murphy, John D.

Further information

• DOI: 10.1016/j.solmat.2023.112457
• URN: urn:nbn:de:bsz:25-freidok-2541388
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 25.03.2025, 1:54 PM CET