钒掺杂Cd1-xMnxTe晶体生长、能级结构及磁光性能研究

As a typical diluted magnetic semiconductor,Cadmium Manganese Telluride (Cd1-xMnxTe or CMT) crystals possess many important applications in the optical fibre communication.Based on the former researches, the development trends are as follows:(1)increase the inherent magneto-optic effect of materials to improve the performance of devices; (2)reduce the optical losses of magneto-optic materials in communications system. This project will study the magneto-optic properties of CMT with vanadium (V) doping. The main researches will be as follows:(1)by optimizing the technology,the Cd0.88Mn0.12Te:V ingot (V concentration is about 6.8 ppm ) will be grown using a Vertical Bridgman method;(2)The Faraday rotation and the photorefractive effect of this crystal will be experimentized, then, the V concentrations will be optimized through the test results;(3) Analyze the effect of the densities,mobilities，photoionisation cross sections and the recombination rates of electrons and holes.Based on the above results,the energy -level model for CMT:V crystals will be built;(4)Study the effect of V doping on the Faraday rotation and the photorefrective property of CMT:V crystals, and special efforts will be put on the analysis of the influence mechanism;(5)Finally,CMT isolator for 980nm will be fabricated with our crystals, and insertion loss,extinctivity will be assessed by performance test of this CMT isolator.The researches of this project on CMT will dish up relibale foundation of theory and practice for further development in the optical fibre communications.

Cd1-xMnxTe（简称CMT）是典型的稀磁半导体，在光纤通信领域具有非常重要的应用。针对国内外在此领域的研究现状，目前主要的发展趋势是提高CMT晶体本征法拉第旋转等磁光效应，增加器件效能和降低材料的光损耗。本项目瞄准钒（V）对CMT晶体磁光性能的影响进行研究。首先，采用垂直布里奇曼法在最优化的生长工艺条件下制备出Cd0.88Mn0.12Te:V（V 为6.8ppm）单晶体；通过对晶体法拉第效应和光折变效应的测试分析，把V 的掺杂量调整到最佳值；然后，分析杂质能级中电子和空穴浓度、迁移率、电离截面、复合率等对CMT晶体能级结构的影响，建立掺杂晶体能级结构模型；研究V掺杂对CMT晶体法拉第效应和光折变效应的影响，并对其机理进行研究；最后，用得到的晶体进行980nm光隔离器试制，并对光隔离器的插入损耗和消光率等进行评价。此结果为CMT晶体在光纤通信领域的进一步发展提供可靠的理论和实验依据。

碲锰镉(Cd1-xMnxTe, CMT) 材料是一类重要的x射线和r射线探测器材料，同时在光 纤通信领域也具有非常重要的应用，用于制作传感器等小功率器件。本项目以掺钒的Cd0 .9Mn0.1Te:V晶体为研究对象，旨在通过掺钒来调节提高晶体质量和材料的磁光性能，磁光性能主要是法拉第效应和磁致光折射效应。首先，采用Te溶液垂直布里奇曼法在最优 化的工艺条件下成功地制备出了掺钒浓度为1.0*10的17次方at/cm3和5.0*10的17次方at/cm3的晶锭，通过钒的调节使Cd0.9Mn0.1Te:V的电阻率高达10的10次方Ω·cm。用固定光强度的方法在自搭建测试仪器上进行了法拉第效应实验，分析 了钒掺杂引起法拉第效应的变化机理为：通过钒的掺杂，使晶体中的空位等缺陷数目减少，自由激子浓度增大从而导致sp-d交换相互作用增强。使法拉第效应在767nm处高达1369.5度/cm·T。通过对双光束耦合增益系数的研究，确定了达到最大增益时的最佳角度。通过PL谱等分析，建立了Cd0.9Mn0.1Te:V晶体能级结构模型。最后，进行了780 nm光隔离器试制，对其隔离度进行了测试。此结果为Cd1-xMnxTe材料在光纤通讯领域、 传感器领域的进一步应用提供了可靠的理论和实验依据。