碲锌镉晶体的铟碲共掺杂退火研究

Study on Indium-Tellurium Co-Doping Annealing in CdZnTe Crystals

针对生长态碲锌镉晶体缺陷密度大和电学性能无法满足室温核辐射探测器的制备要求等问题,研究了铟碲共掺杂退火对碲锌镉晶体碲夹杂和电学性能的影响。利用分子动力学方法模拟了不同温度下铟原子在碲锌镉晶体中的扩散过程,获得了铟原子的扩散系数表达式,计算了铟原子扩散至碲锌镉晶体所需理论时长,在此基础上开展了铟碲共掺杂退火实验,进一步优化了退火工艺。实验结果表明,铟碲共掺杂退火70 h的碲锌镉晶体碲夹杂密度下降至27.61 mm^(-2),体电阻率接近1011Ω·cm、漏电流低于4 nA(400 V),电学性能达到核辐射探测器应用要求。

The high density of defects within the CdZnTe crystals in the growth state,such as tellurium(Te)inclusions,could degrade the electrical performance of CdZnTe room-temperature nuclear radiation detectors.In this paper,the effect of indium-tellurium co-doping annealing on the Te inclusions and electrical properties of CdZnTe crystals is studied.First,the diffusion process of indium atoms in CdZnTe crystals at different diffusion temperatures is simulated by molecular dynamics,and the expression of diffusion coefficients of indium atoms is obtained.Then,the theoretical time required for indium atoms to diffuse into CdZnTe crystals is calculated,based on which indium-tellurium co-doping annealing experiments are carried out to further optimize the annealing process.The experimental results show that the Te intercalation density of the CdZnTe crystals decreases to 27.61 mm^(-2) after 70 h indium-tellurium co-doping annealing,the bulk resistivity increases to about 1011Ω·cm,and the leakage current is below 4 nA(400 V).The electrical properties of the crystal meet the requirements for nuclear radiation detector applications.