Abstract
Axially heterostructured nanowires are a promising platform for next generation electronic and optoelectronic devices. Reports based on theoretical modeling have predicted more complex strain distributions and increased critical layer thicknesses than in thin films, due to lateral strain relaxation at the surface, but the understanding of the growth and strain distributions in these complex structures is hampered by the lack of high-resolution characterization techniques. Here, we demonstrate strain mapping of an axially segmented GaInP-InP 190 nm diameter nanowire heterostructure using scanning X-ray diffraction. We systematically investigate the strain distribution and lattice tilt in three different segment lengths from 45 to 170 nm, obtaining strain maps with about 10−4 relative strain sensitivity. The experiments were performed using the 90 nm diameter nanofocus at the NanoMAX beamline, taking advantage of the high coherent flux from the first diffraction limited storage ring MAX IV. The experimental results are in good agreement with a full simulation of the experiment based on a three-dimensional (3D) finite element model. The largest segments show a complex profile, where the lateral strain relaxation at the surface leads to a dome-shaped strain distribution from the mismatched interfaces, and a change from tensile to compressive strain within a single segment. The lattice tilt maps show a cross-shaped profile with excellent qualitative and quantitative agreement with the simulations. In contrast, the shortest measured InP segment is almost fully adapted to the surrounding GaInP segments. [Figure not available: see fulltext.].
Original language | English (US) |
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Pages (from-to) | 2460-2468 |
Number of pages | 9 |
Journal | Nano Research |
Volume | 13 |
Issue number | 9 |
DOIs | |
State | Published - Sep 1 2020 |
Funding
We acknowledge the excellent support from the staff at the MAX IV Laboratory, in particular Gerardina Carbone for the preparations at the NanoMAX beamline. The MAX IV Laboratory receives funding through the Swedish Research Council under grant no 2013-02235. This research was funded by the Röntgen-Angström Cluster, NanoLund, Marie Sklodowska Curie Actions, Cofund, Project INCA 600398, and the Swedish Research Council grant number 2015-00331. L. J. L. and M. O. H. acknowledge support of NSF DMR 1611341 and 1905768. M. O. H. acknowledges support of the NSF GRFP and the NSF GROW program. We acknowledge the excellent support from the staff at the MAX IV Laboratory, in particular Gerardina Carbone for the preparations at the NanoMAX beamline. The MAX IV Laboratory receives funding through the Swedish Research Council under grant no 2013-02235. This research was funded by the R?ntgen-Angstr?m Cluster, NanoLund, Marie Sklodowska Curie Actions, Cofund, Project INCA 600398, and the Swedish Research Council grant number 2015-00331. L. J. L. and M. O. H. acknowledge support of NSF DMR 1611341 and 1905768. M. O. H. acknowledges support of the NSF GRFP and the NSF GROW program. Funding note: Open access funding provided by Lund University. Acknowledgements
Keywords
- MAX IV
- X-ray diffraction (XRD)
- finite element modeling
- heterostructure
- nanowire
- strain mapping
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- General Materials Science
- Condensed Matter Physics
- Electrical and Electronic Engineering