Ubbink Reinout F, Speelman Tom, Esteban Daniel Arenas, van Leeuwen Mourijn, Stam Maarten, Bals Sara, De Wijs Gilles A, van Eck Ernst R H, Houtepen Arjan J
Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
ACS Nano. 2025 Jan 14;19(1):1150-1158. doi: 10.1021/acsnano.4c13110. Epub 2024 Dec 30.
InP/ZnSe/ZnS core/shell/shell quantum dots are the most investigated quantum dot material for commercial applications involving visible light emission. The inner InP/ZnSe interface is complex since it is not charge balanced, and the InP surface is prone to oxidation. The role of oxidative defects at this interface has remained a topic of debate, with conflicting reports of both detrimental and beneficial effects on the quantum dot properties. In this study we probe the structure of the InP/ZnSe interface at the atomic level using P, Se and O ssNMR and HAADF-STEM. We observe clear differences in Se NMR spectra and crystal orientation of core and shell when the InP/ZnSe is oxidized on purpose. High levels of interface oxidation result in an amorphous phosphate layer at the interface, which inhibits epitaxial growth of the ZnSe shell.
InP/ZnSe/ZnS核/壳/壳量子点是用于涉及可见光发射的商业应用中研究最多的量子点材料。内部InP/ZnSe界面很复杂，因为它电荷不平衡，且InP表面易于氧化。该界面处氧化缺陷的作用一直是一个争论的话题，关于其对量子点性质的有害和有益影响有相互矛盾的报道。在本研究中，我们使用P、Se和O的固体核磁共振（ssNMR）以及高角度环形暗场扫描透射电子显微镜（HAADF-STEM）在原子水平上探测InP/ZnSe界面的结构。当故意氧化InP/ZnSe时，我们观察到核与壳的Se NMR光谱和晶体取向存在明显差异。高水平的界面氧化会在界面处形成非晶态磷酸盐层，这会抑制ZnSe壳的外延生长。
