【作者】 左鸣；

【导师】 张庶元；

【作者基本信息】 中国科学技术大学 ， 凝聚态物理， 2010， 博士

【摘要】 本论文主要探索在溶剂热的条件下制备硫属半导体低维纳米材料的方法,并对所制备的纳米材料进行了微结构表征,对其生长机理也进行了研究,同时还通过调控反应条件来控制产物的形貌及物理性质。主要内容可总结如下：1.在乙二胺和水的混合溶剂中以溶剂热法低温合成了一维纤锌矿ZnS纳米线,纳米线生长方向一致,都沿着[001]方向生长。同时,通过调节乙二胺和水的体积比,达到了ZnS的形貌和结构调控,发现在不断增加水的体积条件下ZnS由薄片向线再向颗粒转换,物相也由六方相到六方立方共存再到立方相。同时也探讨了乙二胺在ZnS纳米线生长过程中的作用和产物的形成机理,提出了立方相ZnS自催化生长六方相ZnS纳米线的生长机制。同时还研究了产物的光致发光性能。这一反应体系还可以推广到其它Ⅱ-Ⅵ半导体纳米材料的制备方面。2.采用简单的水热法制备出了ZnS掺杂Mn·的纳米线。实验中通过调节Mn掺杂量的加入,控制合成了不同形貌的ZnS纳米晶。在低浓度锰掺杂下,得到了掺杂较为均匀的纤锌矿ZnS纳米线；在高浓度猛掺杂下,得到的是纤锌矿ZnS纳米线和立方相ZnS纳米颗粒。而且锰在立方相中的比例要远高于其在六方相中高很多。对于这一结构的形成机理以及锰在不同物相ZnS中的存在方式做了详细的探讨。同时细致研究了产物的光致发光性能的变化与锰掺杂浓度的关系。初步探索了产物的磁性,讨论了其作为稀磁半导体的可能性。3.通过注射法在油酸中快速反应制备了ZnCdS三元混晶量子点。量子点表现出极窄的发光峰以及较高的量子效率。通过调节Zn与Cd的配比,达到了对量子点尺寸的控制。通过对产物吸收光谱和发光光谱的研究,探讨了Zn、Cd组分不同比例是调制对能带宽度的重要因素,它要远大于量子尺寸本身的影响。同时还研究了反应时间对最终产物性质的影响。更多还原

【Abstract】 The aim of this dissertation is to explore synthetic methods for low-dimension semiconducting of chalcogenides besides oxides.The as-prepared nano-materials are characterized and their growth mechanism is also investigated.Meanwhile,we realized to control the morphology of the products and physical properties by adjusting the reaction conditions.The major contents can be summarized as follows:1.One dimensional wurtzite ZnS nanowires were synthesized by using ethylenediamine and distilled water as solvents at low temperature.All the nanowires grow alone [001] direction.Meanwhile, the phase and shape controllable synthesis has been realized by tuning the volume ratio of ethylenediamine and distilled water. The morphology of products changes from nanosheets to nanowires and to nanoparticles finally;and the phase of the products transfers from hexagonal to hexagonal-cubic coexisted and to cubic finally. Based on the experimental results,the role of he solvent and the formation mechanism were discussed and first proposed an new self-catalytic growth mechanism to prepare hexagonal ZnS from cubic ZnS.The optical properties were also investigated.This solvothermal technique could be extended to other Ⅱ-Ⅵ secmiconductor materials.2.A simple solvothermal technique has been developed to synthesize ZnS nanowires doped with Mn. In the experiments, different morphology of ZnS:Mn nanocrystallines were achieved by adjusting the Mn content. In low concentration Mn2+, wurzite ZnS nanorods were synthesized with uniform Mn content; In high concentration Mn2+,wurzite ZnS nanorods and cubic nanoparticles were co existed and Mn content is higher in cubic ZnS than in hexagonal ZnS.A possible formation mechanism for the growth and different Mn2+location in ZnS lattice were discussed. The photoluminescence properties by altering the Mn concentration are also investigated, and the reason for the change are discussed. The Magnetic properties are characterized by ESR spectrum and the results reveals that ZnS:Mn system is not suitable for dilute magnetic semiconductor material.3.A facile chemical route to sizecontrollable high-quality ternary alloyed ZnxCd1-xS nanocrystals in oleic acid via a hot-injection approach. Quantum dots exhibit narrow FWHL and high quantum efficiency. The size of quantum dots are controllable by adjusting the ratio of Zn and Cd.Based on the the results of UV-vis and PL spectrum, the ratio of Zn and Cd instead of quantum size is the key factor to tune the energy bands of ZnCdS.Time-dependent experiments were also investigated.更多还原