@article{3d204102ee8142cdb03105c5b5a7d35c,
title = "Correlated nanoscale analysis of the emission from wurtzite versus zincblende (In,Ga)As/GaAs nanowire core-shell quantum wells",
abstract = "While the properties of wurtzite GaAs have been extensively studied during the past decade, little is known about the influence of the crystal polytype on ternary (In,Ga)As quantum well structures. We address this question with a unique combination of correlated, spatially resolved measurement techniques on core-shell nanowires that contain extended segments of both the zincblende and wurtzite polytypes. Cathodoluminescence hyperspectral imaging reveals a blue-shift of the quantum well emission energy by 75 ± 15 meV in the wurtzite polytype segment. Nanoprobe X-ray diffraction and atom probe tomography enable k·p calculations for the specific sample geometry to reveal two comparable contributions to this shift. First, there is a 30% drop in In mole fraction going from the zincblende to the wurtzite segment. Second, the quantum well is under compressive strain, which has a much stronger impact on the hole ground state in the wurtzite than in the zincblende segment. Our results highlight the role of the crystal structure in tuning the emission of (In,Ga)As quantum wells and pave the way to exploit the possibilities of three-dimensional band gap engineering in core-shell nanowire heterostructures. At the same time, we have demonstrated an advanced characterization toolkit for the investigation of semiconductor nanostructures.",
keywords = "(In,Ga)As quantum well, Nanowire, atom probe tomography, cathodoluminescence, nanofocused X-ray diffraction, polytype",
author = "Jonas L{\"a}hnemann and Hill, {Megan O.} and Jes{\'u}s Herranz and Oliver Marquardt and Guanhui Gao and {Al Hassan}, Ali and Arman Davtyan and Hruszkewycz, {Stephan O.} and Holt, {Martin V.} and Chunyi Huang and Irene Calvo-Almaz{\'a}n and Uwe Jahn and Ullrich Pietsch and Lauhon, {Lincoln J.} and Lutz Geelhaar",
note = "Funding Information: The authors would like to thank Hanno K?pers and Oliver Brandt for discussions and Michael Hanke for a critical reading of the manuscript. The authors are grateful to M. H?ricke and C. Stemmler for MBE maintenance. The authors are also grateful for assistance from M.J. Moody and Z. Sun in performing nanoXRD measurements. O.M. acknowledges support from the DFG through SFB 787. L.J.L. and M.O.H. acknowledge support of NSF DMR-1611341. M.O.H. acknowledges support of the NSF GRFP. X-ray nanodiffraction experiments and data reduction were supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences (BES), Materials Science and Engineering Division. The nanodiffraction measurements were performed at the Hard X-ray Nanoprobe beamline 26-ID-C operated by the Center for Nanoscale Materials and Advanced Photon Source at Argonne National Laboratory. Use of the Center for Nanoscale Materials and the Advanced Photon Source was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DE-AC02-06CH11357. This work made use of the EPIC facility of the NUANCE Center at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. Atom-probe tomography was performed at the Northwestern University Center for Atom-Probe Tomography (NUCAPT). The LEAP tomograph at NUCAPT was purchased and upgraded with grants from the NSF-MRI (DMR-0420532) and ONR-DURIP (N00014-0400798, N00014-0610539, N00014-0910781, N00014-1712870) programs. NUCAPT received support from the MRSEC program (NSF DMR-1720139) at the Materials Research Center, the SHyNE Resource (NSF ECCS-1542205), and the Initiative for Sustainability and Energy (ISEN) at Northwestern University.",
year = "2019",
month = jul,
day = "10",
doi = "10.1021/acs.nanolett.9b01241",
language = "English (US)",
volume = "19",
pages = "4448--4457",
journal = "Nano Letters",
issn = "1530-6984",
publisher = "American Chemical Society",
number = "7",
}