The electronic structure of CdSe/CdS core/shell seeded nanorods: type-I or quasi-type-II?
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. The overlap of the electron density with the core region depends markedly on the size of the CdSe core. For small cores, we observe little overlap, consistent with type-II behavior. For large cores, significant core-overlap of a number of excitonic states can lead to type-I behavior. When electron-hole interactions are taken into account, the core-overlap is further increased. Our calculations indicate that the observed transition from type-II to type-I is largely due to simple volume effects and not to band alignment.
School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University , Tel Aviv 69978, Israel.
Hagai
H
Eshet
Michael
M
Grünwald
Eran
E
Rabani
D002104:Cadmium / Q000737:chemistry; D019187:Cadmium Compounds / Q000737:chemistry*; D057145:Nanoshells / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry
D019187:Cadmium Compounds; D018036:Selenium Compounds; D013440:Sulfides; D002104:Cadmium; C058667:cadmium selenide