Prasad Sarangapani

Motivation:

• Self-assembled QDs offer ability to optimize performancey changing device dimensions
• QD lab deployed on nanoHUB ffers such a simulation platform
• Simulations range from simplistic particle in a box problem to れalistic structures in 10 band tightびnding model

Strain Calculation:

• Multilayer QD composed of different materials => Lattice mismatch and strain
• Alters the electron and hole energy levels
• Valence Force Field (VFF) based strain model with Keating potential used to solve for the relaxed atom positions

Confined states Calculation:

• Schrodinger’s equation solved on the relaxed QD structure
• Can simulate both simplistic EM based model or a 10 band Tight Binding (TB) model in sp3d5s* basis (with SO coupling)
• Visualize the spatial distribution of electronic/hole wave functions

Output visualization and Usage:

• Can obtain relevant outputs such as ぽtical absorption spectrum, strain℅mponents and local bandstructure
• Used by 300+ users worldwide till date. モre than 5000+ users since deploymentf first version of tool in 2005.