溶剂熔区移动法生长Cd0.9Zn0.1Te晶体的工艺优化研究

摘要

To overcome the shortages of high growth temperature, low single crystal ratio and inhomogeneous composition of Cd0.9Zn0.1Te(CZT) crystal growth, the In-doped CZT crystal was grown by traveling heater method through optimized growth process parameters. High quality CZT crystals with diameter of 45 mm were grown after optimizing crystal growth temperature, temperature gradient at solid-liquid interface andin-situ annealing process, which had high resistivity, high transmittance, excellent uniformity, and low concentration of Te inclusions. Moreover, the patterns of wafer and powder X-ray diffraction showed that the crystallinity and the segregation of CZT were improved. Infrared transmittance spectra indicated that the level of impurities and defects was low in the crystal and the overall infrared transmittance of the crystal was about 60%. And UV-visible light absorption spectrum presented good uniformity of the crystal. Te inclusions in the crystal were observed by Infrared microscope, and it was found that Te inclusions were mainly distributed between 0–10μm. In addition, mobility-life product for electrons of the crystal obtained was 8×10–4cm2/V by direct current photoconductivity technique.%为了解决Cd0.9Zn0.1Te(CZT)晶体生长温度高、单晶率低、成分不均匀等问题,采用溶剂熔区移动法(THM)在优化工艺参数下生长了掺In的CZT晶体,在优化晶体的生长温度、固液界面处的温度梯度、原位退火过程等生长条件后,生长出直径为45 mm的低Te夹杂浓度、高电阻率、高透过率、均匀的高质量CZT晶体.X射线衍射结果显示,晶体的结晶性较好、Zn成分轴向偏析小.红外透过光谱测试结果显示,晶体内部的杂质、缺陷水平相对较少,晶体整体的红外透过率在60%左右.紫外-可见光吸收光谱测试结果也进一步表明,晶体的均匀性良好.采用红外显微镜对晶体内部的Te夹杂形貌及其尺寸进行观察,结果表明Te夹杂的尺寸主要分布在0~10μm之间.采用直流稳态光电导技术测得电子的迁移率寿命积约为8×10-4 cm2/V.