碲锌镉单晶体的正电子寿命研究

Study on the Positron Annihilation Lifetime in Cd_(1-x)Zn_xTe Crystal

用正电子湮没技术(PAT)研究了原料富Cd改进布里奇曼法生长的碲锌镉单晶样品退火前后的缺陷。刚生长的样品缺陷寿命值较高,其内部存在的点缺陷主要是占优势的Cd空位,用富Cd同成份源Cd1-xZnxTe气氛对样品在不同温度下等时退火后,发现样品的正电子寿命参数对退火温度表现出很强的依赖关系,通过对样品退火过程中空位的迁移、聚集及消失情况分析,得出较适宜的退火温度约为700℃。

Cd1-xZnxTe crystals were prepared by the improved Bridgman method from cadmium-rich materials. The defects in the as-grown and annealed samples are investigated by positron annihilation technology in this paper. It was found that the lifetime of the defects in the as-grown samples had a long time and the point defects were mainly cadmium vacancies which were preponderant in Cd1-xZnxTe crystal. It was found that the positron annihilation lifetime heavily depended upon the annealing temperature after annealing in the same ingredient atmosphere of cadmium-rich Cd1-xZnxTe at the different temperatures,and the optimal annealing temperature was around 700℃ by testing and analyzing the movement, congregation and disappearance of the vacancies during annealing process.