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

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:Objective:Optical emission at 1.5μm without GaNUnderstand experimental data on QD spectra in selective overgrowthApproach: Model large structure60nm x 60nm x 60nm9 million atomsNo changes to the published tight binding parametersResult:Match experiment remarkably well Strain change in quantum dot aspect ratio Quantitative model of complex systemStudied sensitivity to experimental imperfections – small variationsEffective mass theories provided the wrong guidance