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Mesostructured germanium with cubic pore symmetry

Naturevolume 441pages11221125 (2006) | Download Citation

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Abstract

Regular mesoporous oxide materials have been widely studied1,2,3,4,5,6,7,8 and have a range of potential applications, such as catalysis, absorption and separation. They are not generally considered for their optical and electronic properties. Elemental semiconductors with nanopores running through them represent a different form of framework material with physical characteristics contrasting with those of the more conventional bulk, thin film and nanocrystalline forms1. Here we describe cubic mesostructured germanium, MSU-Ge-1, with gyroidal channels containing surfactant molecules, separated by amorphous walls that lie on the gyroid (G) minimal surface as in the mesoporous silica MCM-48 (ref. 2). Although Ge is a high-melting, covalent semiconductor that is difficult to prepare from solution polymerization, we succeeded in assembling a continuous Ge network using a suitable precursor for Ge4- atoms. Our results indicate that elemental semiconductors from group 14 of the periodic table can be made to adopt mesostructured forms such as MSU-Ge-1, which features two three-dimensional labyrinthine tunnels obeying space group symmetry and separated by a continuous germanium minimal surface that is otherwise amorphous. A consequence of this new structure for germanium, which has walls only one nanometre thick, is a wider electronic energy bandgap (1.4 eV versus 0.66 eV) than has crystalline or amorphous Ge. Controlled oxidation of MSU-Ge-1 creates a range of germanium suboxides with continuously varying Ge:O ratio and a smoothly increasing energy gap.

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Acknowledgements

We thank C. Malliakas for his help with the PDF data processing. We thank the National Science Foundation for financial support.

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Affiliations

  1. Department of Chemistry, Michigan State University, East Lansing, Michigan, 48824, USA

    • Gerasimos S. Armatas
    •  & Mercouri G. Kanatzidis

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Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Corresponding author

Correspondence to Mercouri G. Kanatzidis.

Supplementary information

  1. Supplementary Notes

    This file contains Supplementary Figures and Legends 1–2 and Supplementary Discussions about the chemical environment of Ge atoms of MSU-Ge-1 semiconductor by X-ray photoelectron spectroscopy (XPS) experiments; including Supplementary Figure 3. (DOC 1077 kb)

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https://doi.org/10.1038/nature04833

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