Epitaxial Ge0.81Sn0.19 nanowires for nanoscale mid-infrared emitters

Michael S. Seifner, Alain Dijkstra, Johannes Bernardi, Andreas Steiger-Thirsfeld, Masiar Sistani, Alois Lugstein, Jos E.M. Haverkort, Sven Barth (Corresponding author)

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Samenvatting

Highly oriented Ge 0.81Sn 0.19 nanowires have been synthesized by a low-temperature chemical vapor deposition growth technique. The nanostructures form by a self-seeded vapor-liquid-solid mechanism. In this process, liquid metallic Sn seeds enable the anisotropic crystal growth and act as a sole source of Sn for the formation of the metastable Ge 1-xSn x semiconductor material. The strain relaxation for a lattice mismatch of ϵ = 2.94% between the Ge (111) substrate and the constant Ge 0.81Sn 0.19 composition of nanowires is confined to a transition zone of <100 nm. In contrast, Ge 1-xSn x structures with diameters in the micrometer range show a 5-fold longer compositional gradient very similar to epitaxial thin-film growth. Effects of the Sn growth promoters' dimensions on the morphological and compositional evolution of Ge 1-xSn x are described. The temperature- and laser power-dependent photoluminescence analyses verify the formation of a direct band gap material with emission in the mid-infrared region and values expected for unstrained Ge 0.81Sn 0.19 (e.g., band gap of 0.3 eV at room temperature). These materials hold promise in applications such as thermal imaging and photodetection as well as building blocks for group IV-based mid- to near-IR photonics.

Originele taal-2Engels
Pagina's (van-tot)8047-8054
Aantal pagina's8
TijdschriftACS Nano
Volume13
Nummer van het tijdschrift7
DOI's
StatusGepubliceerd - 23 jul 2019

Citeer dit

Seifner, M. S., Dijkstra, A., Bernardi, J., Steiger-Thirsfeld, A., Sistani, M., Lugstein, A., ... Barth, S. (2019). Epitaxial Ge0.81Sn0.19 nanowires for nanoscale mid-infrared emitters. ACS Nano, 13(7), 8047-8054. https://doi.org/10.1021/acsnano.9b02843