Simulation Tools for Strain Engineering, Manufacturing and Design of Novel Optical and Electronic Superlattice Materials and Surfaces

The overall objective of this program is to create a predictive model based on molecular dynamics (MD) to simulate the growth of three material systems of great technological importance: InGaN/GaN, CdTe/ZnTe/Si:As and CdTe/GaAs. InGaN/GaN quantum dot (QD) heterostructures have attracted a great deal of theoretical and experimental interest because of their applications in QD lasers, optical memories, QD photodetectors and quantum computing, among others. CdTe/ ZnTe/Si:As and CdTe/GaAs are composite substrates that have the potential to eliminate many of the drawbacks of the substrates currently employed in HgCdTe-based infrared focal plane arrays. Specifically, ab-initio density functional theory calculations will be performed to determine accurate parameters for the various interatomic potentials to be employed in MD growth simulations. Once the potential parameters have been optimized through tests with experimental partners, MD simulations of the heteroepitaxial growth will be performed. The parameter space of actual growths, such as substrate surface preparation, growth temperature, material fluxes, and the thicknesses of interfacial layers, will be explored. Defect formation will be studied as the growth proceeds and the strain in the simulated structures will be calculated. Finally, the tradeoffs in the choice of growth parameters will be explored.