Sena Hoshino, Shuji Oi, Yu Ogura, Tatsuya Yokoi, Yan Li, Atsutomo Nakamura, Katsuyuki Matsunaga
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引用次数: 0
Abstract
It was experimentally reported that light illumination leads to reduced deformation stresses in some III-V compound semiconductors such as GaP. This phenomenon is known as the negative photoplastic effect, which is expected to originate from interactions between photoexcited carriers and glide dislocations. To clarify its physical origin at the atomic and electronic levels, density-functional-theory calculations were performed for Shockley partial dislocations in GaP. In the absence of excess carriers, both Ga and P cores of the partial dislocations were found to have reconstructed structures that are energetically most stable. This can be understood by the fact that dangling-bond-like states at undercoordinated atoms of the dislocation cores are removed by core reconstruction. In the presence of excess carriers that would be formed by light illumination, the reconstructed Ga and P cores were able to trap excess holes and electrons, respectively, and were subsequently transformed to unreconstructed structures. It was also found that the unreconstructed structures due to excess carriers tend to have smaller potential barrier heights for dislocation glide, as compared to the pristine reconstructed structures without any excess carriers. This is in good agreement with the increased dislocation mobility in GaP under external light illumination that has been experimentally reported.
据实验报告,光照会导致某些 III-V 族化合物半导体(如 GaP)的变形应力减小。这种现象被称为负光塑性效应,预计源于光激发载流子与滑行位错之间的相互作用。为了在原子和电子水平上阐明其物理起源,我们对 GaP 中的肖克利 30∘ 部分位错进行了密度函数理论计算。结果发现,在没有过量载流子的情况下,部分位错的 Ga 核和 P 核都具有能量最稳定的重构结构。这可以从差排核心中配位不足的原子上的类悬空键态被核心重构所消除这一事实中得到解释。在光照下会形成过剩载流子的情况下,重构的镓核和铂核能够分别捕获过剩的空穴和电子,随后转变为非重构结构。研究还发现,与没有过剩载流子的原始重构结构相比,过剩载流子导致的非重构结构往往具有较小的位错滑行势垒高度。这与实验报告的 GaP 在外部光照下位错迁移率增加的现象十分吻合。
期刊介绍:
Physical Review Materials is a new broad-scope international journal for the multidisciplinary community engaged in research on materials. It is intended to fill a gap in the family of existing Physical Review journals that publish materials research. This field has grown rapidly in recent years and is increasingly being carried out in a way that transcends conventional subject boundaries. The journal was created to provide a common publication and reference source to the expanding community of physicists, materials scientists, chemists, engineers, and researchers in related disciplines that carry out high-quality original research in materials. It will share the same commitment to the high quality expected of all APS publications.