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Title: Very High Refractive Index Transition Metal Dichalcogenide Photonic Conformal Coatings by Conversion of ALD Metal Oxides

Materials for nanophotonic devices ideally combine ease of deposition, very high refractive index, and facile pattern formation through lithographic templating and/or etching. In this work, we present a scalable method for producing high refractive index WS 2 layers by chemical conversion of WO 3 synthesized via atomic layer deposition (ALD). These conformal nanocrystalline thin films demonstrate a surprisingly high index of refraction (n > 3.9), and structural fidelity compatible with lithographically defined features down to ~10 nm. Although this process yields highly polycrystalline films, the optical constants are in agreement with those reported for single crystal bulk WS 2. Subsequently, we demonstrate three photonic structures - first, a two-dimensional hole array made possible by patterning and etching an ALD WO 3 thin film before conversion, second, an analogue of the 2D hole array first patterned into fused silica before conformal coating and conversion, and third, a three-dimensional inverse opal photonic crystal made by conformal coating of a self-assembled polystyrene bead template. Furthermore these results can be trivially extended to other transition metal dichalcogenides, thus opening new opportunities for photonic devices based on high refractive index materials.
Authors:
ORCiD logo [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Univ. degli Studi di Milano-Bicocca, Milano (Italy)
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 9; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1503660

Chen, Christopher T., Pedrini, Jacopo, Gaulding, E. Ashley, Kastl, Christoph, Calafiore, Giuseppe, Dhuey, Scott, Kuykendall, Tevye R., Cabrini, Stefano, Toma, Francesca M., Aloni, Shaul, and Schwartzberg, Adam M.. Very High Refractive Index Transition Metal Dichalcogenide Photonic Conformal Coatings by Conversion of ALD Metal Oxides. United States: N. p., Web. doi:10.1038/s41598-019-39115-3.
Chen, Christopher T., Pedrini, Jacopo, Gaulding, E. Ashley, Kastl, Christoph, Calafiore, Giuseppe, Dhuey, Scott, Kuykendall, Tevye R., Cabrini, Stefano, Toma, Francesca M., Aloni, Shaul, & Schwartzberg, Adam M.. Very High Refractive Index Transition Metal Dichalcogenide Photonic Conformal Coatings by Conversion of ALD Metal Oxides. United States. doi:10.1038/s41598-019-39115-3.
Chen, Christopher T., Pedrini, Jacopo, Gaulding, E. Ashley, Kastl, Christoph, Calafiore, Giuseppe, Dhuey, Scott, Kuykendall, Tevye R., Cabrini, Stefano, Toma, Francesca M., Aloni, Shaul, and Schwartzberg, Adam M.. 2019. "Very High Refractive Index Transition Metal Dichalcogenide Photonic Conformal Coatings by Conversion of ALD Metal Oxides". United States. doi:10.1038/s41598-019-39115-3. https://www.osti.gov/servlets/purl/1503660.
@article{osti_1503660,
title = {Very High Refractive Index Transition Metal Dichalcogenide Photonic Conformal Coatings by Conversion of ALD Metal Oxides},
author = {Chen, Christopher T. and Pedrini, Jacopo and Gaulding, E. Ashley and Kastl, Christoph and Calafiore, Giuseppe and Dhuey, Scott and Kuykendall, Tevye R. and Cabrini, Stefano and Toma, Francesca M. and Aloni, Shaul and Schwartzberg, Adam M.},
abstractNote = {Materials for nanophotonic devices ideally combine ease of deposition, very high refractive index, and facile pattern formation through lithographic templating and/or etching. In this work, we present a scalable method for producing high refractive index WS2 layers by chemical conversion of WO3 synthesized via atomic layer deposition (ALD). These conformal nanocrystalline thin films demonstrate a surprisingly high index of refraction (n > 3.9), and structural fidelity compatible with lithographically defined features down to ~10 nm. Although this process yields highly polycrystalline films, the optical constants are in agreement with those reported for single crystal bulk WS2. Subsequently, we demonstrate three photonic structures - first, a two-dimensional hole array made possible by patterning and etching an ALD WO3 thin film before conversion, second, an analogue of the 2D hole array first patterned into fused silica before conformal coating and conversion, and third, a three-dimensional inverse opal photonic crystal made by conformal coating of a self-assembled polystyrene bead template. Furthermore these results can be trivially extended to other transition metal dichalcogenides, thus opening new opportunities for photonic devices based on high refractive index materials.},
doi = {10.1038/s41598-019-39115-3},
journal = {Scientific Reports},
number = 1,
volume = 9,
place = {United States},
year = {2019},
month = {2}
}

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Atomically Thin MoS2 A New Direct-Gap Semiconductor
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Photonic band-gap structures
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