人工晶体学报, 2020, 49 (10): 1794, 网络出版: 2021-01-09
6H-SiC单晶的中子辐照损伤及其退火特性研究
Radiation Damage and Annealing Characteristics of Neutron-Irradiated 6H-SiC Single Crystals
中子辐照 缺陷 晶格损伤 退火回复 吸收光谱 6H-SiC 6H-SiC neutron-irradiation defect lattice damage annealing recovery absorption spectra
摘要
用剂量为1.72×1019 n/cm2和1.67×1020 n/cm2的中子对掺氮6H-SiC单晶进行辐照,利用紫外-可见(UV-Vis)吸收光谱等方法研究了辐照引起的晶格损伤及随退火温度的回复过程。结果表明:中子辐照产生的大量缺陷使SiC的光吸收明显增加;光学带隙能随辐照剂量的增加而降低,这与禁带中引入的局域态缺陷能级有关。光吸收边出现强烈的连续吸收可能归因于辐照产生的不同类型缺陷簇或局部非晶区域的光散射。对两个剂量辐照的样品进行室温到1 600 ℃的等时退火,发现两个剂量辐照产生的晶格损伤所需的退火回复温度不同,但退火回复过程都呈现出以800 ℃为转折点的两个相同阶段。
Abstract
The lattice damage and annealing recovery of N-doped 6H-SiC under neutron irradiation with fluences of 1.72×1019 n/cm2 and 1.67×1020 n/cm2 was investigated by UV-Vis absorption spectroscopy. The results indicate that the significant increase of optical absorption and the decrease of band-gap energy in neutron-irradiated sample is assigned to localized energy level in the forbidden energy band induced by the accumulation of irradiated defects. A continuous strong absorption with many fine structures appeared near the band-edge after irradiation, the origin of which would be attributed to the presence of various different structures of defect clusters and localized amorphous zones. The irradiated samples with two fluences are isochronal annealed from room temperature to 1 600 ℃, the evolution of the absorption spectrum with the annealing temperature shows that the recovery temperature of the lattice damage for the irradiated sample with two fluences is different, but the annealing recovery process shows two same stages with 800 ℃ as the turning temperature.
黄丽, 阮永丰. 6H-SiC单晶的中子辐照损伤及其退火特性研究[J]. 人工晶体学报, 2020, 49(10): 1794. HUANG Li, RUAN Yongfeng. Radiation Damage and Annealing Characteristics of Neutron-Irradiated 6H-SiC Single Crystals[J]. Journal of Synthetic Crystals, 2020, 49(10): 1794.