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NUANCE: Nanoscale Characterization Experimental Center

Correlating Photoluminescence and Structural Properties of Uncapped and GaAs-Capped Epitaxial InGaAs Quantum Dots

Technical staff member of NUANCE Jinsong Wu, former postdoc Qianqian Li, and Director Vinayak P. Dravid participated in a study that reported a new way to measure the correlation between structural and photoluminescence (PL) properties of self-assembled semiconductor quantum dots (QDs).

For both research and applications involving optoelectronic devices, the understanding of the relationship between structural and PL properties in such devices is critical. Until recently, the structural and PL properties have been probed from two different epitaxial layers, specifically, top-capped and buried layers respectively. This new report finds for the first time both structural and PL measurements from a single uncapped layer of InGaAs QDs to correlate directly composition, strain and shape of QDs with the optical properties. By using this new method of finding correlations between the two properties, quantum dots can be tuned to obtain desired optical characteristics and properties.

NUANCE’s major contributions to this project were the TEM instruments it provided for sampling purposes.

“The quantum dot samples were taken using our TEM instruments,” explained technical staff member Jinsong Wu. “They helped us to observe the base dimension and height of specific quantum dots.”

The TEM instruments used for this research are found in the EPIC facility of the NUANCE Center. Support for the EPIC facility was given by the SHyNE Resource, the MRSEC Program, and the International Institute of Nanotechnology (IIN), as well as several other benefactors. The full publication can be read here.


TEM images showing the base dimension of a quantum dot (left), and the wetting layer thickness of a quantum dot (right).