通过红外透过成像研究了 Cd/Zn 气氛退火过程中 Cd0．9 Zn0．1 Te∶In 晶体内 Te 夹杂的密度及尺寸分布的演变.结果发现,Cd/Zn 气氛退火前,晶体中的 Te 夹杂密度分布比较均匀；退火后,晶体高温端近表面区域的 Te 夹杂密度较退火前提高了...通过红外透过成像研究了 Cd/Zn 气氛退火过程中 Cd0．9 Zn0．1 Te∶In 晶体内 Te 夹杂的密度及尺寸分布的演变.结果发现,Cd/Zn 气氛退火前,晶体中的 Te 夹杂密度分布比较均匀；退火后,晶体高温端近表面区域的 Te 夹杂密度较退火前提高了1个数量级,而晶体内部的 Te 夹杂密度则较退火前降低了1个数量级,且其密度沿温度梯度方向逐渐增加.退火前,晶体表面和内部的 Te 夹杂的直径主要分布在1~25μm；退火后,在晶体表面,直径＜45μm 的 Te 夹杂密度显著增大；而在晶体内部,直径＜5μm 和＞25μm的 Te 夹杂密度显著增大.导致这些现象的原因是退火过程中,Te 夹杂沿着温度梯度方向不断向晶体表面迁移,在迁移过程中尺寸相近的 Te 夹杂通过合并长大,尺寸相差较大的 Te 夹杂则以 Ostwald 熟化方式长大,并使小尺寸的 Te 夹杂更小.但由于熟化不充分,在 Ostwald 熟化长大过程中留下了很多尺寸＜5μm 的 Te 夹杂颗粒.展开更多
A laser scanning confocal microscope （LSCM） and a field-emission scanning electron microscope （FE- SEM） were used to study the defects in CdMnTe crystals, such as twin boundaries, Te inclusions, and dislocations. ...A laser scanning confocal microscope （LSCM） and a field-emission scanning electron microscope （FE- SEM） were used to study the defects in CdMnTe crystals, such as twin boundaries, Te inclusions, and dislocations. Twin boundaries were usually decorated with Te inclusions, which could induce dislocations. The optical, elec- trical properties and detector performance of CdMnTe crystals with twins and free of twins were compared. The results showed that the wafers with a high density of twins usually had lower average IR transmittance and poorer crystalline quality. Besides, the energy spectra indicated that twin boundaries in a CdMnTe detector had a negative effect on detector performance; the values of both the energy resolution and （μτ）e were nearly half of those for a single crystal detector.展开更多
文摘采用改进的垂直布里奇曼生长法生长Cd Zn Te(CZT)单晶,并在晶体生长后期采取长时间的原位恒温退火.采用红外透射显微镜、I-V特性曲线以及多道能谱仪测试经过原位退火后的晶体内部Te夹杂相分布、电阻率大小以及能谱响应.结果表明,原位退火可以大幅降低CZT晶体内部大尺寸Te夹杂相的密度,晶体内绝大部分的Te夹杂都集中在5μm以内.此外,原位退火后的晶体电阻率从4.54×108Ω·cm上升至3.73×1010Ω·cm.原位退火后的CZT晶体对241Am@59.5 ke Vγ射线表现出了良好的能量分辨率,为7.29%.
基金Projects (50872111, 50902113, 61274081) supported by the National Natural Science Foundation of ChinaProject (2011CB610406) supported by the National Basic Research Program of China+2 种基金Project (B08040) supported by the 111 Project of ChinaProject (JC20100228) supported by Foundation for Fundamental Research of Northwestern Polytechnical University (NPU), ChinaProject (SKLSP201012) supported by the Research Fund of the State Key Laboratory of Solidification Processing (NPU), China
文摘通过红外透过成像研究了 Cd/Zn 气氛退火过程中 Cd0．9 Zn0．1 Te∶In 晶体内 Te 夹杂的密度及尺寸分布的演变.结果发现,Cd/Zn 气氛退火前,晶体中的 Te 夹杂密度分布比较均匀；退火后,晶体高温端近表面区域的 Te 夹杂密度较退火前提高了1个数量级,而晶体内部的 Te 夹杂密度则较退火前降低了1个数量级,且其密度沿温度梯度方向逐渐增加.退火前,晶体表面和内部的 Te 夹杂的直径主要分布在1~25μm；退火后,在晶体表面,直径＜45μm 的 Te 夹杂密度显著增大；而在晶体内部,直径＜5μm 和＞25μm的 Te 夹杂密度显著增大.导致这些现象的原因是退火过程中,Te 夹杂沿着温度梯度方向不断向晶体表面迁移,在迁移过程中尺寸相近的 Te 夹杂通过合并长大,尺寸相差较大的 Te 夹杂则以 Ostwald 熟化方式长大,并使小尺寸的 Te 夹杂更小.但由于熟化不充分,在 Ostwald 熟化长大过程中留下了很多尺寸＜5μm 的 Te 夹杂颗粒.
基金Project supported by the National Natural Science Foundations of China(Nos.50902113,50902114,61274081)the National Basic Research Program of China(No.2011CB610406)+2 种基金the 111 Project of China(No.B08040),the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20116102120014)NPU Foundation for Fundamental Research(No.JC20100228)the Research Fund of the State Key Laboratory of Solidification Processing,China(No.SKLSP201012)
文摘A laser scanning confocal microscope （LSCM） and a field-emission scanning electron microscope （FE- SEM） were used to study the defects in CdMnTe crystals, such as twin boundaries, Te inclusions, and dislocations. Twin boundaries were usually decorated with Te inclusions, which could induce dislocations. The optical, elec- trical properties and detector performance of CdMnTe crystals with twins and free of twins were compared. The results showed that the wafers with a high density of twins usually had lower average IR transmittance and poorer crystalline quality. Besides, the energy spectra indicated that twin boundaries in a CdMnTe detector had a negative effect on detector performance; the values of both the energy resolution and （μτ）e were nearly half of those for a single crystal detector.
