Argonne National Laboratory

Research Highlight | Center for Nanoscale Materials

Complexity in light: tuning quantum well emission through correlative microscopy
In a study published in Nano Letters, researchers demonstrated an advanced characterization toolkit for the investigation of semiconductor nanostructures.
(a) Birds-eye view scanning electron micrograph of the (In,Ga)As core–shell NW ensemble (sample A). Superimposed are monochromatic CL maps of the low-temperature QW emission at 1.35 and 1.39 eV (false color representation using linear intensity scales). The inset shows a top-view illustration of the core–shell geometry. (b) Micrograph of NW A1 together with a map of the crystal phase recorded by EBSD on the upper facet of this NW. (c) Sketch of the axial NW cross-section highlighting how the shell QW is grown on the core segments with different crystal structure.

Scientific Achievement

Nanoscale variations of crystal polytype, strain and com-position in ternary (In,Ga)As quantum well nanostructures locally shift cathodoluminescence emission energy.

Significance and Impact

Crystal structure was found to have a role in tuning quantum well emission. Combining electron, X-ray and atom probe microscopy demonstrates a unique route for advanced nanoscale characterization of photonic heterostructures.

Research Details

  • Cathodoluminescence hyperspectral imaging revealed a blue-shift of emission energy in core-shell quantum well nanowires.
  • This shift was correlated with a local shift of indium revealed by atom probe tomography at Northwestern, and the presence of wurtzite/zincblende polytypes and local lattice strain were identified by the Center for Nanoscale Materials (CNM)/Advanced Photon Source (APS) Hard X-ray Nanoprobe.

Work was performed in part at CNM and APS.

DOI: 10.1021/acs.nanolett.9b01241

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About Argonne’s Center for Nanoscale Materials
The Center for Nanoscale Materials is one of the five DOE Nanoscale Science Research Centers, premier national user facilities for interdisciplinary research at the nanoscale supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge, Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit https://​sci​ence​.osti​.gov/​U​s​e​r​-​F​a​c​i​l​i​t​i​e​s​/​U​s​e​r​-​F​a​c​i​l​i​t​i​e​s​-​a​t​-​a​-​G​lance.

About the Advanced Photon Source

The U. S. Department of Energy Office of Science’s Advanced Photon Source (APS) at Argonne National Laboratory is one of the world’s most productive X-ray light source facilities. The APS provides high-brightness X-ray beams to a diverse community of researchers in materials science, chemistry, condensed matter physics, the life and environmental sciences, and applied research. These X-rays are ideally suited for explorations of materials and biological structures; elemental distribution; chemical, magnetic, electronic states; and a wide range of technologically important engineering systems from batteries to fuel injector sprays, all of which are the foundations of our nation’s economic, technological, and physical well-being. Each year, more than 5,000 researchers use the APS to produce over 2,000 publications detailing impactful discoveries, and solve more vital biological protein structures than users of any other X-ray light source research facility. APS scientists and engineers innovate technology that is at the heart of advancing accelerator and light-source operations. This includes the insertion devices that produce extreme-brightness X-rays prized by researchers, lenses that focus the X-rays down to a few nanometers, instrumentation that maximizes the way the X-rays interact with samples being studied, and software that gathers and manages the massive quantity of data resulting from discovery research at the APS.

This research used resources of the Advanced Photon Source, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

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