基于化学气相传输法的正交相黑磷单晶生长研究

Thin black phosphorus crystals, which are designated as a monolayer or a few layers of phosphorene, have recently emerged as a new member of the 2D material family. They have attracted considerable attentions due to their promising properties. So far, the implementation of thin black phosphorus crystals can be attained mainly by micromechanical cleavage from orthorhombic black phosphorus (o-BP) bulk single crystal. From this perspective, o-BP single crystal is the precursor to attain high-quality thin black phosphorus crystals. In this project, we propose to synthesize large-scale (centimeter size) and high-quality o-BP bulk single crystal based on the chemical vapor transport (CVT) method. The relationship between the reaction system, the temperature gradient and the crystallization behavior of o-BP single crystal will be studied. The reaction mechanism involved in the synthesis of o-BP single crystal by using the CVT method will be explored. The roles of the thermodynamic and kinetic factors in the modulation of the reaction mechanism will be clarified, which is expected to help to solve the science problem regarding the complext allotrope transition of phosphorus. Centimeter-sized and high-quality o-BP bulk single crystal is expected to be attained by optimizing the reaction conditions of CVT method. In the meantime, direct synthesis of thin black phosphorus crystals on a solid substrate will be attempted once the reaction mechanism of CVT method is clear. The implementation of this project will promote the real application of the new 2D material black phosphorus in the electronic and optoelectronic areas.

作为二维材料领域的新成员，单层和少层磷烯（薄层黑磷晶体）以其众多吸引人的物理特性，受到人们的广泛关注。目前，薄层黑磷晶体的获得主要依赖于从正交相黑磷体块单晶剥离得到。因此，高质量正交相黑磷体块单晶是制备薄层黑磷晶体的前提。本项目提出在化学气相传输法的基础上发展一种大尺寸（厘米级）、高质量正交相黒磷体块单晶的制备技术。通过系统研究反应体系、温度梯度与正交相黒磷单晶的结晶行为之间的关系，探索化学气相传输法合成正交相黑磷单晶的反应机理，阐明化学反应过程中的热力学与动力学因素对内在反应机理的调控机制，以解决黒磷单晶生长过程中磷的同素异形体转变的科学难题，并优化工艺条件，获得厘米级的高品质正交相黒磷体块单晶。同时，在深入理解化学气相传输法反应机理的基础上，将尝试采用该方法在固体基底上直接生长薄层黑磷单晶。项目的顺利实施，将进一步推动黑磷这种新型二维材料在电子学以及光电子学领域的实际应用。

高质量正交相黑磷体块单晶是制备二维黑磷材料的前提。本项目通过系统研究反应体系、温度梯度与正交相黒磷单晶的结晶行为之间的关系，揭示了Sn/I2/红磷反应体系化学气相传输法合成黑磷的反应机理，阐明了化学反应过程中的热力学与动力学因素对内在反应机理的调控机制，通过优化工艺条件，获得了大尺寸、高品质正交相黒磷体块单晶。研究了不同基底对薄层黑磷生长的影响，在SiO2/Si基底和蓝宝石衬底上成功生长了小面积的薄层黑磷。此外，还开展了化学气相传输法生长碲掺杂黑磷单晶和液相法制备准单层黑磷的研究，并探索了薄层黑磷在嵌段共聚物自组装、纳米材料细胞毒性、光催化产氢等领域的应用。