超硬半导体磷化硼的制备与表征

Synthesis and Characterization of Superhard Semiconductor Boron Phosphide

桂睿

11749044

硕士

物理学

赵予生

2019-05-14

2019-05-31

哈尔滨工业大学

深圳

电子信息制造业是重要的战略产业，而其基础为半导体的研发与制造，但以硅为代表的第一代半导体与以砷化镓为代表的第二代半导体在其各个应用领域的性能已经逼近其物理极限。在这样的背景下，研究具有高迁移率、高热导率、宽带隙及能在恶劣环境中工作的新型半导体变得尤为重要。磷化硼（BP）是具一种性能优异的候选材料，有着高于其他常见半导体的硬度、高于银与铜的热导率和优异的稳定性。然而，其制备方面的困难限制了人们对它的研究。本课题中，合成了百微米级BP单晶，有着闪锌矿结构并且是透明的，具有2.1 eV的适中带隙。我们的实验结合第一性原理计算，揭示了该化合物存在非常大的应变硬化，因而有着出乎意料的37 GPa渐进硬度，接近超硬材料的40 GPa阈值，是迄今为止，除金刚石与立方氮化硼以外，已知的半导体中的最高硬度。基于第一性原理计算，我们阐明了BP在拉伸和剪切变形下的断裂机制，从理论上发现其与亚稳六方相的形成有关。通过进一步的光谱研究，发现其在13 GPa下发生了异常的电子跃迁，导致BP的共价性逐渐增强。此外，本课题还详细介绍了声子辅助的光致发光过程和光泵浦产生707 nm红激光的现象。该课题的结果使得BP可成为其它超硬材料作为高功率激光设备的参照。

Electronic information manufacturing is an important strategic industry, and its foundation is the research and manufacture of semiconductor. However, the performance of the first generation semiconductor represented by silicon and the second generation semiconductor represented by gallium arsenide in its various application fields has been approaching to its physical limits. In this context, it is particularly important to study next-generation semiconductors with high mobility, high thermal conductivity, wide bandgap, and capable of working at high temperature and in other hostile environments. Boron phosphide, BP, is such an attractive candidate with exceptional properties, which is, however, mainly limited to theoretical study because of the difficulty in sample preparation.In this work, we report the synthesis of large single-crystal BP in millimeter size. The final product has a zincblende structure and is optically transparent with a suitably large bandgap of 2.1 eV. Our experiment, in conjunction with ab initio theory, reveals that the compound exhibits an extraordinary strain stiffening, leading to an unexpectedly high load-invariant hardness of 37 GPa, close to the 40 GPa threshold for superhard materials and the hardest among the known semiconductors except diamond and cBN. Based on the first-principles calculations, the fracture mechanisms in BP under tensile and shear deformations can be attributed to the formation of metastable hexagonal phase. Further spectroscopy study indicates that an unusual electronic transition is occurred at high pressure of 13 GPa, resulting in asymptotically enhanced covalent bonding state. In addition, a phonon-assisted photoluminescence process and evidences for photon-pumped red lasing at 707 nm are also presented in detail. Findings in this work make BP as a benchmark material for diverse applications ranging from superhard tools to high-power lasing devices.

磷化硼 超硬材料 半导体 红激光 高压

boron phosphide superhard materials semiconductors red lasing high pressure

中文

联合培养

南方科技大学

桂睿. 超硬半导体磷化硼的制备与表征[D]. 深圳. 哈尔滨工业大学,2019.