Physics of low dimensional functional materials and Defect Science and Engineering

  • Physics of Quantum Devices for Quantum Information
    • Ordered Quantum Dot Arrays (QDA), Binary Quantum systems for Qubits, and Artificial Molecules,
    • Symmetry violation and Chaos in ordered Quantum Dot arrays, electrode-QD coupling, energy level anti-crossing, electron localization/delocalization, electron tunneling,
    • Coupled semiconductor nanofeatures with mixed scales,
    • Quantum theory for sensing single molecules, and
    • CNT junction based nanosensors.
  • Bandgap engineering of indirect semiconductors
    • Up-conversion for IR enhanced absorption via two-photon absorption, formation of intermediate energy bands in the bandgap, and
    • Down-conversion.
  • Defect Engineering
    • Defect nucleation during crystals growth (silicon  and related materials) and during heterostructure fabrication,
    • Thermal treatment in Si and SiGe and defect annihilation and growth,
    • Stress and Strain in ultra-thin heterostructures and layered stacks, and Relaxation mechanisms,
    • Atomistic and microscale analysis of nanomaterials: Hyperdoping of silicon, and N doped silicon, and
  • Formation of nanofeatures and nano-bodies in functional nanomaterials.
    • Quantum Chemistry and Thermodynamics,
    • Continuum and atomistic modeling of structural, electronic, optical, and mechanical properties of materials affected by defects,
    • Point defect and impurity clustering in N doped monocrystalline and polycrystalline silicon, and
    • Physics of formation and thermodynamic stability of SiGe nanodots using atomistic calculations and continuum theories.
  • Multiscale characterization of defects in high purity semiconductors and nanostructures
  • Novel optical spectroscopic nanoprobe and TEM techniques for characterization of defect structure in functional materials, active defects, deep energy levels, and carrier dynamics (generation, recombination, and transport).

High Efficiency Solar Cells

  • Physics of photon energy harvesting in nano-structured materials 
    • New concepts for high conversion efficiency, targeting Luque and Marti limit,
    • Solid state processes involved in two-photon absorption, and
    • Charge carrier generation, confinement, and recombination in coupled quantum dot arrays.
  • Implementation of new concepts for third generation solar cells
    • Newly discovered N hyperdoping of silicon for making Intermediate Band, and
    • Growth of Si and SiGe nanodots by low thermal budget processing.
  • Some work done on the following:
    • Disorder at the interface of perovskite on silicon (for ultra high efficiency solar cells), and
    • High efficiency nanosctructured photocatlaysts   (for Solar water splitting and Solar conversion of CO2 to alternative fuel).