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In this work, we present an all-gas-phase approach for the synthesis of quantum-confined core/shell nanocrystals (NCs) as a promising alternative to traditional solution-based methods. Spherical quantum dots (QDs) are grown using a single-stage flow-through nonthermal plasma, yielding monodisperse NCs, with a concentric core/shell structure confirmed by electron microscopy. The in-flight negative charging of the NCs by plasma electrons keeps the NC cores separated during shell growth. The success of this gas-phase approach is demonstrated here through the study of Ge/Si core/shell QDs. We find that the epitaxial growth of a Si shell on the Ge QD core compressively strains the Ge lattice and affords the ability to manipulate the Ge band structure by modulation of the core and shell dimensions. This all-gas-phase approach to core/shell QD synthesis offers an effective method to produce high-quality heterostructured NCs with control over the core and shell dimensions.
Bibliographical noteFunding Information:
This work was supported primarily by the U.S. National Science Foundation (NSF) through the University of Minnesota MRSEC under Award DMR-1420013. K.I.H. acknowledges support by the NSF Graduate Research Fellowship Program under Grant 00039202. U.R.K. was supported by the U.S. Department of Energy (DOE), Center for Advanced Solar Photophysics, an Energy Frontier Research Center funded by the U.S. DOE, Office of Science, Basic Energy Sciences. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the NSF through the MRSEC program.
- core/shell nanocrystal
- nonthermal plasma
- strained epitaxy
How much support was provided by MRSEC?
Reporting period for MRSEC
- Period 3
PubMed: MeSH publication types
- Journal Article