材料期刊网

纳米材料的本征性质与其结构密切相关，在纳米尺度操控材料并表征其结构是纳米科学与技术的关键。II–VI半导体ZnSe是重要的电子、光电子材料，采用热蒸发法制备了一种四足结构ZnSe纳米晶，通过高分辨透射电子显微镜对这种四足ZnSe纳米晶的晶体结构进行了表征。该ZnSe纳米晶由一个四面体的立方晶核和四个沿[001]方向生长的六方相分枝构成。本文对这种ZnSe纳米晶的形貌和结构进行了讨论，证明了在ZnSe纳米晶内两种晶相的共存。根据ZnSe的结晶学特性和晶相的温度稳定性，解释了这种四足结构纳米晶的生长机制：ZnSe的四面体立方晶核在高温区域形成后，ZnSe蒸汽在低温区继续沉积在晶核上形成四个六方相的分支足，最终形成了具有立方晶核的ZnSe四足纳米晶。

Manipulation of materials with nanoscale control is the key of nanoscience and nanotechnology, because the intrinsic properties of nanoscale materials are closely determined by their structures. As an important II–VI semiconductor, ZnSe-based nanostructures have been the subject of intense interest in view of their wide-ranging applications in electronics and optoelectronics. In this work, a tetrapod-shaped ZnSe nanostructure was synthesized successfully via thermal evaporation and their crystallographic structures were characterized by high-resolution transmission electron microscope. The morphology and construction of ZnSe nanostructure are discussed in detail. The as-grown ZnSe tetrapods include one zinc blende nucleus and four arms with uniform wurtzite structure growing along the [001] direction. And the co-existence of two crys?tal structures in different domains of one ZnSe nanocrystal is experimentally demonstrated. According to the crystal phase stability in different temperature regions and crystallographic property of ZnSe, an acceptable growth model is employed to explain the formation process of this newly discovered ZnSe tetrapods nanocrystal.