Hg1-xCdxTe晶体缺陷的正电子湮没寿命

利用正电子(e⁺)湮没寿命谱实验研究了Hg_1-xCd_xTe晶体样品的空位缺陷.碲溶剂法生长的样品，不论是n型导电还是p型导电都存在大量的Hg空位.经过合适的退火工艺，p型材料转为n型，同时对正电子的俘获效应减小，表现为正电子湮没平均寿命值减小14—17ps.若退火温度高于350℃，正电子湮没寿命值又增大，表明Hg空位浓度增加.得到HgCdTe中正电子的体寿命为τ_b=272ps.根据正电子湮没寿命和电参数的测量结果，得出 关键词：

POSITRON ANNIHILATION TIME STUDY OF DEFECTS IN Hg1-xCdxTe SINGLE CRYSTALS

We have studied the vacancy type defects of the HgCdTe crystals by using positron annihilation time technique.Samples grown by Te solution method accommodate a large amount of Hg vacancies,no matter what kind of conducting type(n type or p type) they are.By suitable annealling process the as-grown p-type samples can be turned into n-type,and the traping of the positrons decreased(the positron annihilation time decreases by 14—17ps).If the samples are annealled at higher temperatrue,the positron annihilation time will increase.This indicates that the Hg vacancies are increased.The bulk time of the positron annihilation in HgCdTe we obtained in this experiment is 272ps.According to the positron annihilation time and the electric parameters of the samples,we obtain the appropriate annealling temperature is 180—220℃.