An efficient and deterministic photon management using deep subwavelength features

Ashish Prajapati, Jordi Llobet, Mariana Antunes, Sofia Martins, Helder Fonseca, Carlos Calaza, João Gaspar, Gil Shalev

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Light trapping and the broadband absorption of the solar radiation are significant to a plethora of absorption-based photonic devices. Specifically, efficient broadband absorption was recently demonstrated with arrays of subwavelength structures. The current study examines both numerically and experimentally light trapping driven by deep sidewall subwavelength structures (DSSS) in silicon nanopillar (NP) arrays (DSSS arrays). Particularly, the focus is on DSSS geometries that are an inherent outcome of the top-down dry etch approach used in arrays of high aspect ratio NPs due to the periodical operationality of the Bosch dry etch method. ~10% enhancement in the broadband absorption of DSSS arrays compared with NP arrays is demonstrated numerically, as well as the generation of near-IR absorptivity peaks of ~25% for DSSS arrays. Importantly, it is shown that the introduction of DSSS systematically blue-shifts the absorptivity peaks of the NP arrays and in this manner a deterministic light trapping is possible. Finally, decrements of ~40% in direct reflectivity and ~7% in diffused reflectivity in DSSS arrays realized on silicon wafers is demonstrated experimentally.

Original languageEnglish
Article number104521
JournalNano Energy
Volume70
DOIs
StatePublished - 1 Apr 2020

Keywords

  • Broadband absorption of solar radiation
  • Deep subwavelength structures
  • Light trapping
  • Metamaterials
  • Nanopillar arrays

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science (all)
  • Electrical and Electronic Engineering

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