Radiation-induced mobility of small defect clusters in covalent materials

Abstract

Although defect clusters are detrimental to electronic and mechanical properties of semiconductor materials, annihilation of such clusters is limited by their lack of thermal mobility due to high migration barriers. Here, we find that small clusters in bulk SiC (a covalent material of importance for both electronic and nuclear applications) can become mobile at room temperature under the influence of electron radiation. So far, direct observation of radiation-induced diffusion of defect clusters in bulk materials has not been demonstrated yet. This finding was made possible by low angle annular dark field (LAADF) scanning transmission electron microscopy (STEM) combined with non-rigid registration technique to remove sample instability, which enables atomic resolution imaging of small migrating defect clusters. We show that the underlying mechanism of this athermal diffusion is ballistic collision between incoming electrons and cluster atoms. Our findings suggest that defect clusters may be mobile under certain irradiation conditions, changing current understanding of cluster annealing process in irradiated covalent materials.

References in corpus (4)

• From Point Defects in Graphene to Two-Dimensional Amorphous Carbon
• Stone-Wales--type transformations in carbon nanostructures driven by electron irradiation
• Imaging Atomic-Level Random Walk of a Point Defect in Graphene
• Modeling of long-term defect evolution in heavy-ion irradiated 3C-SiC: Mechanism for thermal annealing and influences of spatial correlation

Cited by in corpus (2)

• Evolution of small defect clusters in ion-irradiated 3C-SiC: combined cluster dynamics modeling and experimental study
• Optimization of self-interstitial clusters in 3C-SiC with Genetic Algorithm