Improvement of carrier diffusion length in silicon nanowire arrays using atomic layer deposition

Shinya Kato, Yasuyoshi Kurokawa, Shinsuke Miyajima, Yuya Watanabe, Akira Yamada, Yoshimi Ohta, Yusuke Niwa, masaki Hirota

Research output: Contribution to journalLetterpeer-review

38 Citations (Scopus)


To achieve a high-efficiency silicon nanowire (SiNW) solar cell, surface passivation technique is very important because a SiNW array has a large surface area. We successfully prepared by atomic layer deposition (ALD) highquality aluminum oxide (Al2O3) film for passivation on the whole surface of the SiNW arrays. The minority carrier lifetime of the Al2O3-depositedSiNW arrays with bulk silicon substrate was improved to 27 μs at the optimum annealing condition. To remove the effect of bulk silicon, the effective diffusion length of minority carriers in the SiNW array was estimated by simple equations and a device simulator. As a result, it was revealed that the effective diffusion length in the SiNW arrays increased from 3.25 to 13.5 μm by depositing Al2O3 and post-annealing at 400°C. This improvement of the diffusion length is very important for application to solar cells, and Al2O3 deposited by ALD is a promising passivation material for a structure with high aspect ratio such as SiNW arrays.

Original languageEnglish
Article number361
Pages (from-to)1-8
Number of pages8
JournalNanoscale Research Letters
Issue number1
Publication statusPublished - Nov 14 2013
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics


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