Multimodal Analysis of InAs/InGaAlAs Quantum Dots Using Transmission Electron Microscopy and Atom Probe Tomography

Abstract

Owing to the recent development of small and complex electronic devices, there has been a strong demand for the improvement of analysis techniques. Scanning transmission electron microscopy (STEM) and atom probe tomography (APT) are powerful methods for analyzing these devices; however, each method alone provides limited insights. To overcome these limitations and improve device performance, it is crucial to perform multimodal analysis by combining the aforementioned techniques. In this study, we have analyzed multilayered self-assembled InAs quantum dots (QDs) embedded in an InGaAlAs spacer layer on an InP(311)B substrate. Self-assembled InAs QDs are widely used in optoelectronic and photovoltaic devices owing to their discrete energy levels and bandgap corresponding to the infrared region. In this presentation, we present the details of the analysis process and local 3D compositional and strain distribution reflecting the shape of the QDs. Such insights into the correlation of the parameters of the QDs are unique to multimodal analysis.

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