碲镉汞电子结构缺陷的正电子湮灭研究

An Experimental Investigation on the Defects in Hg_(1-x)Cd_x Te by Positron Annihilation Technique

碲镉汞(Hg_(1-x)Cd_xTe,或称MCT),是60年代问世的一种性能优良的红外探测材料,它的电性能在很大程度上取决于电子结构中的缺陷:自然缺陷(空穴、填隙原子、空位和络化物等);扩散缺陷(位错、晶粒边界、沉积、熔点物和非掺入的杂质等).键稳模型断言,在MCT中,a.缺陷的形成和动态特性是热激活的;b.Hg-Te键很弱,汞空位是主要的自然缺陷;c.大多数扩散缺陷是电激活的.但是,迄今不能清楚地说明缺陷形成的动态过程及其与材料电性能的关系.正电子湮没技术(PAT)对于研究原子尺度的缺陷极其敏感.本文以PAT为手段,研究MCT退火过程中,缺陷浓度与电阻率的关系,以及充分退火后MCT的电阻率与温度的关系.

Hg-(1-x)Cd_x Te (or MCT) is a material widely used for the infrared detector, The electric property of MCT is mainly determined by the defects in its electronic structure, Positron annihilation together with resistivity measurement techniques have been used to investigate the defects and their effects on electric resistance. Samples of MCT were annealed for 20 minutes at temperatures from 22℃ to 360℃ and annihilation parameters and resistances were measured for each specified temperature. Satisfactory results have been obtained.