Wednesday, July 24, 2013

1307.6097 (Hagai Eshet et al.)

The Electronic Structure of CdSe/CdS Core/Shell Seeded Nanorods: Type-I
or Quasi-Type-II?

Hagai Eshet, Michael Grunwald, Eran Rabani
The electronic structure of CdSe/CdS core/shell seeded nanorods of experimentally relevant size is studied using a combination of molecular dynamics and semiempirical pseudopotential techniques, with the aim to address the transition from type-I to a quasi-type-II band alignment. The hole is found to be localized in the core region regardless of its size. When electron-hole interactions are neglected, we observe little overlap of electron density with the core region, consistent with type-II behavior. When electron-hole interactions are taken into account, we find that the overlap of the electron density with the core decreases with decreasing size, consistent with a transition to quasi-type II. We attribute this transition to an interplay of electron-hole interactions and volume effects, and not to band alignment. Our results provide insight to both scanning tunneling and optical measurements.
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