Capitán María J, Álvarez Jesús, Puebla Sergio, Spilsbury Michael J, Conde Julio J, Juárez Beatriz H, Otero Roberto
Instituto de Estructura de la Materia, CSIC c/Serrano 119 28006 Madrid Spain
Física de Sistemas Crecidos con Baja Dimensionalidad, Universidad Autónoma de Madrid Unidad asociada al CSIC Spain.
RSC Adv. 2019 Dec 16;9(71):41531-41539. doi: 10.1039/c9ra09184j. eCollection 2019 Dec 13.
During the past decade, due to their large number of technological applications, a large number of research studies have been devoted to CdSe nanocrystal (NC) systems. Most of the studies of NC grown on substrates present in the literature correspond to a submonolayer coverage. However, interparticle interactions and, consequently, system morphology and its properties can change at higher coverage regime. We combine the X-ray diffraction technique at wide and small angle range with direct space AFM microscopy for the morphological characterization of samples in the monolayer vicinity. We conclude that the CdSe preserves its nanoparticle character and its pyramid shape. This nanoparticle character is also reflected in the CdSe Density Of States (DOS) measured by UPS. We have shown that the particle CdSe atoms are perfectly ordered. They form nanocrystals with a wurtzite structure, grown with an axial and lateral matching with the HOPG substrate lattice in a hexagonal arrangement up to the monolayer coverage, with a strong interaction with the substrate. Above the monolayer coverage this epitaxial match is looser, resulting in a 3D disorder growth.
在过去十年中，由于其大量的技术应用，大量的研究致力于CdSe纳米晶体（NC）系统。文献中大多数关于在衬底上生长的NC的研究都对应于亚单层覆盖。然而，在更高的覆盖度下，粒子间相互作用以及系统形态及其性质可能会发生变化。我们将广角和小角范围的X射线衍射技术与直接空间原子力显微镜相结合，用于表征单层附近样品的形态。我们得出结论，CdSe保留了其纳米颗粒特性及其金字塔形状。这种纳米颗粒特性也反映在通过紫外光电子能谱（UPS）测量的CdSe态密度（DOS）中。我们已经表明，CdSe颗粒原子排列完美。它们形成具有纤锌矿结构的纳米晶体，在单层覆盖之前，以六边形排列与HOPG衬底晶格轴向和横向匹配生长，与衬底有强烈相互作用。在单层覆盖之上，这种外延匹配变得更松散，导致三维无序生长。
