Rudra Sourav, Rao Dheemahi, Poncé Samuel, Saha Bivas
Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
Nano Lett. 2023 Sep 13;23(17):8211-8217. doi: 10.1021/acs.nanolett.3c02350. Epub 2023 Aug 29.
Low hole mobility of nitride semiconductors is a significant impediment to realizing their high-efficiency device applications. Scandium nitride (ScN), an emerging rocksalt indirect band gap semiconductor, suffers from low hole mobility. Utilizing the Boltzmann transport formalism including spin-orbit coupling, here we show the dominating role of ionized impurity scattering in reducing the hole mobility in ScN thin films. We suggest a route to increase the hole mobility by reversing band ordering through strain engineering. Our calculation shows that the biaxial tensile strain in ScN lifts the split-off hole band above the heavy hole and light hole bands, leading to a lower hole-effective mass and increasing mobility. Along with the impurity scattering, the Fröhlich interaction also plays a vital role in the carrier scattering mechanism due to the polar nature of ScN. Increased hole mobility in ScN will lead to higher efficiencies in thermoelectric, plasmonics, and neuromorphic computing devices.
氮化物半导体的低空穴迁移率是实现其高效器件应用的一个重大障碍。氮化钪（ScN）是一种新兴的岩盐型间接带隙半导体，存在空穴迁移率低的问题。利用包括自旋轨道耦合在内的玻尔兹曼输运形式，我们在此表明电离杂质散射在降低ScN薄膜中空穴迁移率方面起主导作用。我们提出了一条通过应变工程反转能带排序来提高空穴迁移率的途径。我们的计算表明，ScN中的双轴拉伸应变将分裂出的空穴带提升到重空穴带和轻空穴带之上，导致空穴有效质量降低并提高迁移率。除了杂质散射外，由于ScN的极性，弗罗利希相互作用在载流子散射机制中也起着至关重要的作用。ScN中空穴迁移率的提高将导致热电、等离子体和神经形态计算设备的效率更高。
