Internal structure of InP/ZnS nanocrystals unraveled by high-resolution soft X-ray photoelectron spectroscopy.
High-energy resolution photoelectron spectroscopy (DeltaE < 200 meV) is used to investigate the internal structure of semiconductor quantum dots containing low Z-contrast elements. In InP/ZnS core/shell nanocrystals synthesized using a single-step procedure (core and shell precursors added at the same time), a homogeneously alloyed InPZnS core structure is evidenced by quantitative analysis of their In3d(5/2) spectra recorded at variable excitation energy. When using a two-step method (core InP nanocrystal synthesis followed by subsequent ZnS shell growth), XPS analysis reveals a graded core/shell interface. We demonstrate the existence of In-S and S(x)-In-P(1-x) bonding states in both types of InP/ZnS nanocrystals, which allows a refined view on the underlying reaction mechanisms.
Huang
Kai
K
CEA Grenoble, INAC/SPrAM, UMR 5819 CEA-CNRS-UJF/LEMOH, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France.
Demadrille
Renaud
R
Silly
Mathieu G
MG
Sirotti
Fausto
F
Reiss
Peter
P
Renault
Olivier
O