Evolution of ion-irradiated point defect concentration by cluster dynamics simulation*

Abstract

The relationship between ions irradiation and the induced microstructures (point defects, dislocations, clusters, etc.) could be better analyzed and explained by simulation. The mean field rate theory and cluster dynamics are used to simulate the effect of implanted Fe on the point defects concentration quantitatively. It is found that the depth distribution of point defect concentration is relatively gentle than that of damage calculated by SRIM software. Specifically, the damage rate and point defect concentration increase by 1.5 times and 0.6 times from depth of 120 nm to 825 nm, respectively. With the consideration of implanted Fe ions, which effectively act as interstitial atoms at the depth of high ion implantation rate, the vacancy concentration C v decreases significantly after reaching the peak value, while the interstitial atom concentration C i increases significantly after decline of the previous stage. At the peak depth of ion implantation, C v dropped by 86%, and C i increased by 6.2 times. Therefore, the implanted ions should be considered into the point defects concentration under high dose of heavy ion irradiation, which may help predict the concentration distribution of defect clusters, further analyzing the evolution behavior of solute precipitation.

Online English Teaching System Based on Internet of Things Technology

“…Based on this research, the author has developed an online English language course based on the Internet of Things technology [9,10]. For example, in college, the author studies the SPOC format of English art, develops a comprehensive curriculum based on Internet of Things technology, develops measurement tools and standards, teaches English online, improves real-time online English language teaching, and improves teaching quality [11,12].…”

First-principles study of stability of point defects and their effects on electronic properties of GaAs/AlGaAs superlattice

“…[5][6][7][8] However, when the SL materials are used in irradiation environments such as aerospace field, [9] high energy physics field, [10] and nuclear physics field, [11] point defects may appear in GaAs/AlAs SL, resulting in the failure of the SL-based devices. [12,13] Thus, it is important to improve the performance of GaAs/AlAs SL structure under irradiation. Recently, Jiang et al carried out ab-initio molecular dynamics (AIMD) calculations to explore its behaviors under electron irradiation and confirmed the experimental observation that the radiation resistance of GaAs/AlAs SL is enhanced by the introduction of Ga into AlAs layer.…”