Internal Structure of InP/ZnS Nanocrystals Unraveled by High-Resolution Soft X-ray Photoelectron Spectroscopy

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• 作者：Kai Huang ; Renaud Demadrille ; Mathieu G. Silly ; Fausto Sirotti ; Peter Reiss ; Olivier Renault
• 刊名：ACS Nano
• 出版年：2010
• 出版时间：August 24, 2010
• 年：2010
• 卷：4
• 期：8
• 页码：4799-4805
• 全文大小：378K
• 年卷期：0
• ISSN：1936-086X

文摘

High-energy resolution photoelectron spectroscopy (ΔE < 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.