Nanoelectronic Modeling Lecture 32: Strain Layer Design through Quantum Dot TCAD

By Gerhard Klimeck1, Muhammad Usman1

1. Electrical and Computer Engineering, Purdue University, West Lafayette, IN

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This presentation demonstrates the utilization of NEMO3D to understand complex experimental data of embedded InAs quantum dots that are selectively overgrown with a strain reducing InGaAs layer. Different alloy concentrations of the strain layer tune the optical emission and absorption wavelength of the quantum dots. The role of the non-linear strain behavior ovserved in the experimental data is explored in NEMO3D. The simulation engine serves as a virtual microscope to understand the interplay of disorder, strain, and quantum dot shape.

Learning Objectives:

  1. Objective:
    1. Optical emission at 1.5μm without GaN
    2. Understand experimental data on QD spectra in selective overgrowth
  2. Approach:
    1. Model large structure
    2. 60nm x 60nm x 60nm
    3. 9 million atoms
    4. No changes to the published tight binding parameters
  3. Result:
    1. Match experiment remarkably well
      1. Strain
      2. change in quantum dot aspect ratio
    2. Quantitative model of complex system
    3. Studied sensitivity to experimental imperfections – small variations
    4. Effective mass theories provided the wrong guidance

Cite this work

Researchers should cite this work as follows:

  • Gerhard Klimeck; Muhammad Usman (2010), "Nanoelectronic Modeling Lecture 32: Strain Layer Design through Quantum Dot TCAD,"

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