Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 7: II-VI semiconductors

HL 7.2: Talk

Monday, February 25, 2008, 11:45–12:00, EW 201

First principles calculations of CdSe nanowires — •Marcel Mohr and Christian Thomsen — Institut für Festkörperphysik, TU Berlin

We present first principles calculations of CdSe nanowires with diameters of up to 25 Å. Their atomic structure and their electronic and vibrational properties are investigated. We verify the strong band gap dependence on nanowire diameter. In addition, passivating the surface dangling bonds increases the band gap. The phonon modes that correspond to bulk modes show a redshift with smaller diameter. A shortening of the bond lengths of surface atoms gives rise to high-energy surface modes. Surface termination induces lattice contraction and a shift of the phonon frequencies.