Basic physical properties of cubic boron arsenide
Basic physical properties of cubic boron arsenide
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DOI：
10.1063/1.5116025
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发表时间：
2019-09-16
影响因子：
4
通讯作者：
Hu, Yongjie
中科院分区：
文献类型：
--
作者：
Kang, Joon Sang;Li, Man;Hu, Yongjie
立方砷化硼（BAs）是一种新兴的半导体材料，具有创纪录的高导热性，在电子热管理方面的应用备受关注。然而，由于高质量的BAs单晶是最近才获得的，因此BAs的许多基本性质仍未在实验中得到探索。在这里，我们报告了BAs重要物理性质的系统实验测量，包括带隙、光学折射率、弹性模量、剪切模量、泊松比、热膨胀系数和热容。利用光吸收和法布里-珀罗干涉，在室温下测得1.82 eV的光带隙和3.29 （657 nm）的折射率。采用基于超快光泵探针光谱的皮超声方法测量了高弹性模量326 GPa，是硅的两倍。此外，使用温度相关x射线衍射测量了3.85 x 10(-6) K-1的线性热膨胀系数；这个值非常接近GaN等原型半导体，这强调了BAs在冷却高功率和高频电子产品方面的前景。我们还进行了从头算理论计算，实验结果与理论结果吻合良好。重要的是，这项工作旨在为BAs的基本物理性质建立一个数据库（表1），期望这种半导体将激发电子、光子学和力学方面的广泛研究和应用。
Cubic boron arsenide (BAs) is an emerging semiconductor material with a record-high thermal conductivity subject to intensive research interest for its applications in electronics thermal management. However, many fundamental properties of BAs remain unexplored experimentally since high-quality BAs single crystals have only been obtained very recently. Here, we report the systematic experimental measurements of important physical properties of BAs, including the bandgap, optical refractive index, elastic modulus, shear modulus, Poisson's ratio, thermal expansion coefficient, and heat capacity. In particular, light absorption and Fabry-Perot interference were used to measure an optical bandgap of 1.82 eV and a refractive index of 3.29 (657 nm) at room temperature. A picoultrasonic method, based on ultrafast optical pump probe spectroscopy, was used to measure a high elastic modulus of 326 GPa, which is twice that of silicon. Furthermore, temperature-dependent X-ray diffraction was used to measure a linear thermal expansion coefficient of 3.85 x 10(-6) K-1; this value is very close to prototype semiconductors such as GaN, which underscores the promise of BAs for cooling high power and high frequency electronics. We also performed ab initio theory calculations and observed good agreement between the experimental and theoretical results. Importantly, this work aims to build a database (Table I) for the basic physical properties of BAs with the expectation that this semiconductor will inspire broad research and applications in electronics, photonics, and mechanics.