Nanostructure Electronic Band Modeling for Solar Cell and Lighting Applications

Quantum dots (QDs) and nanowires (NWs) are being investigated as potential alternatives to conventional thin film optoelectronic devices. These nanostructures have the potential to partially relieve the strain caused by lattice mismatch between two materials. The accumulated strain at interfaces leads to defect generation which degrades device performance. QDs and NWs have electronic transition levels which differ significantly from that of the bulk material, therefore, a model is necessary to understand the effects of confinement, strain, and polarization effects on these energy levels. Here we implement and validate a model to compute transition energies of nanostructures based on k.p theory with continuum elasticity for strain. We apply our model to study the impact of strain on the formation and electronic structure of QDs and NWs in the context of novel solar cells or light emitting devices. Our model enables us to understand the impact of geometry, configuration, and composition of QDs and NWs on the transition wavelengths in order to predict which characteristics will provide improvements in device efficiency.