DFT calculations of carrier-trapping effects on atomic structures of 30° partial dislocation cores in zincblende II-VI group zinc compounds
DFT calculations of carrier-trapping effects on atomic structures of 30° partial dislocation cores in zincblende II-VI group zinc compounds
复制标题
DFT计算闪锌矿II-VI族锌化合物中30°部分位错核原子结构的载流子捕获效应
DOI：
10.1103/physrevmaterials.7.013603
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发表时间：
2023
影响因子：
3.4
通讯作者：
K. Matssunaga
中科院分区：
文献类型：
--
作者：
S. Hoshino;Y. Oshima;T. Yokoi;A. Nakamura;K. Matssunaga
据实验报道，II-VI族无机半导体晶体在外部光照射下变得更硬和更脆。为了揭示光照效应的基本因素，本文对ZnSe和ZnTe中的30°部分位错进行了系统的计算，并与前人报道的ZnS的结果进行了讨论。在这三个晶体系统中发现，原始部分位错的核心具有未重构的原子结构，而它们的核心通过捕获过量载流子而更有利地进行原子重构。这种载流子捕获和位错核心的原子重建归因于由于宿主晶体的离子键合特征而在核心处存在过量的静电势。位错核的重建降低了部分位错的势能，并可以反过来增加Peierls势垒的位错滑移，对应于所观察到的硬化和脆性由光照。由于位错核心重建的能量增益也取决于带隙内出现的缺陷诱导能级的能量位置。
It was experimentally reported that II-VI group inorganic semiconductor crystals become harder and brittle by external light illumination. In order to reveal essential factors of the light illumination effect, systematiccalculations are performed for 30° partial dislocations in ZnSe and ZnTe, and the obtained results are discussed together with those for ZnS reported previously. It is found in these three crystal systems that the cores of pristine partial dislocations have unreconstructed atomic structures whereas their cores undergo atomic reconstruction energetically more favorably by trapping excess carriers. Such carrier trapping and atomic reconstruction of the dislocation cores are ascribed to the presence of excess electrostatic potentials at the cores due to ionic bonding characters of the host crystals. The dislocation core reconstructions decrease potential energies of the partial dislocations and can in turn increase Peierls-potential barriers for dislocation glide, corresponding to the observed hardening and brittleness by light illumination. The energy gains due to the dislocation-core reconstructions also depend on energy positions of the defect-induced levels that appear within the band gaps.