Role of structural and compositional details in atomistic tight-binding calculations for InN nanocrystals

A theoretical investigation of structural and optical properties of semiconductor InN nanocrystals is reported. The numerical scheme starts with single-particle calculations using atomistic tight-binding model including sp3s⁎sp3s⁎ orbitals, spin–orbit coupling, and nearest-neighbor interaction. On the basis of single-particle states computed by tight-binding theory, the band gaps, density of states, electron–hole coulombic energies, and emission spectra are plotted as functions of core diameter. Results obtained from the compositions of the nanocrystal centers located on anions and cations are compared. Geometric structures with wurtzite and zinc-blende structures are also compared. It is concluded that efficient control of electronic structures and optical properties of InN nanocrystals may be achieved theoretically by varying the size, composition, and geometric structure. The diameters of InN nanocrystals used in biological and medical applications are approximately >3.25 nm, which correspond to energies in the infrared region. Finally, data on size, structure, composition, as well as structural and optical properties of InN nanocrystals may be used to develop novel InN-based nanodevices.