Epitaxial Ge<sub>0.81</sub>Sn<sub>0.19</sub> Nanowires for Nanoscale Mid-Infrared Emitters.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31282653.
- Also identified by DOI 10.1021/acsnano.9b02843.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Highly oriented Ge<sub>0.81</sub>Sn<sub>0.19</sub> 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<sub>1-<i>x</i></sub>Sn<sub><i>x</i></sub> semiconductor material. The strain relaxation for a lattice mismatch of ε = 2.94% between the Ge (111) substrate and the constant Ge<sub>0.81</sub>Sn<sub>0.19</sub> composition of nanowires is confined to a transition zone of <100 nm. In contrast, Ge<sub>1-<i>x</i></sub>Sn<sub><i>x</i></sub> 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<sub>1-<i>x</i></sub>Sn<sub><i>x</i></sub> 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<sub>0.81</sub>Sn<sub>0.19</sub> (<i>e</i>.<i>g</i>., 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.