Efficient light trapping and broadband absorption of the solar spectrum in nanopillar arrays decorated with deep-subwavelength sidewall features

Yevgeny Faingold, Shay Fadida, Ashish Prajapati, Jordi Llobet, Mariana Antunes, Helder Fonseca, Carlos Calaza, João Gaspar, Gil Shalev

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Silicon nanopillar (NP) arrays are known to exhibit efficient light trapping and broadband absorption of solar radiation. In this study, we consider the effect of deep subwavelength sidewall scalloping (DSSS) on the broadband absorption of the arrays. Practically, the formation of DSSS is a side effect of top-down dry etching of NP arrays of several microns height. We use finite-difference time-domain electromagnetic calculations to show that the presence of DSSS can result in efficient excitation of optical modes in both the arrays and the underlying substrates. We demonstrate a broadband absorption enhancement of >10% in a DSSS-NP array with an underlying substrate. Finally, we use device calculations to examine the effect of DSSS on the electrical performance of a photovoltaic cell, as the main concern is the degradation of the open-circuit voltage due to surface recombination (DSSS results in higher surface-to-volume ratio). We show that the effect of DSSS on open-circuit voltage is negligible. Finally, deep-subwavelength sidewall features offer a new, interesting photon management strategy towards absorption enhancement.

Original languageEnglish
Pages (from-to)18613-18621
Number of pages9
JournalNanoscale
Volume10
Issue number39
DOIs
StatePublished - 21 Oct 2018

ASJC Scopus subject areas

  • Materials Science (all)

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