【作者】 周旋；

【导师】 张联盟； 王传彬；

【作者基本信息】 武汉理工大学 ， 材料学， 2013， 硕士

【摘要】 微纳电子技术的迅猛发展,催生了利用电子的自旋自由度来设计量子器件的自旋电子学。近年来,过渡金属掺杂ZnO基稀磁半导体材料在自旋电子学基础理论和自旋电子器件应用方面都表现出越来越重要的研究价值。对Co掺杂ZnO稀磁半导体纳米粉体材料的深入研究具有重要的科学意义和应用价值。本论文采用溶胶凝胶-煅烧法和溶胶凝胶-自燃法制备不同掺杂含量的Zm1-XCoXO纳米粉体,研究工艺参数和掺杂含量对纳米粉体结构和磁学性能的影响。本论文研究的主要内容和结论如下：采用溶胶凝胶-煅烧法制备Zm1-XCoXO纳米粉体,研究陈化条件和煅烧温度对Zn0.95Co0.05O纳米粉体结构及磁学性能的影响,研究掺杂含量对Zm1-XCoXO纳米粉体微观结构和磁学性能的影响。结果表明,溶胶需在100℃温度下进行,适宜的陈化时间为3天；Zn0.95Co0.05O纳米粉体在未煅烧和煅烧温度为700℃以下时,均出现Co3O4杂相峰,当煅烧温度达到800℃时,Co3O4分解成CoO后以Co2+形式再次固溶进入ZnO的晶格,形成Zn0.95Co0.05O单相；当Co的掺杂含量达到和超过7%时,800℃煅烧得到的Zm1-XCoXO纳米粉体均出现Co3O4杂相；溶胶凝胶-煅烧法制备的Zm1-XCoXO纳米粉体中Co的固溶度略高于5%。经800℃煅烧的Zm1-XCoXO纳米粉体均表现出室温顺磁性,并且随着Co掺杂浓度的增加,纳米粉体的顺磁性增强。采用溶胶凝胶-自燃法制备Zm1-XCoXO纳米粉体,研究掺杂含量和后续热处理的煅烧温度对Zm1-XCoXO纳米粉体结构及磁学性能的影响。研究发现,Co的固溶度略高于7%,掺杂含量达到和超过10%时,样品中出现Co单质；对Zm1-XCoXO纳米粉体进行后续煅烧热处理,Zn0.93Co0.07O纳米粉体仍为纯相,Co掺杂含量大于等于10%的样品中Co单质氧化生成Co3O4,煅烧温度达到800℃时,Zn0.9Co0.1O纳米粉体中少量的Co3O4发生分解以Co2+形式再次固溶进入ZnO晶格。溶胶凝胶-自燃法制备的Zn0.93Co0.07O纳米表现出室温铁磁性,但是随着煅烧温度的升高,铁磁性减弱并表现为顺磁性,当煅烧温度为800℃时,样品仅表现出明显的顺磁性,这种磁性的转变很可能是来源于样品中载流子输运特征的变化。比较溶胶凝胶-煅烧法和溶胶凝胶-自燃法制备的Zm1-XCoXO纳米粉体的结构和磁学性能。由于反应过程的不同,两种方法制备的Zm1-XCoXO纳米粉体中Co的固溶度存在差异,产生的杂相也不同。溶胶凝胶-自燃法反应迅速,容易造成缺氧的环境,得到Co单质杂相；溶胶凝胶-煅烧法在氧气充足的环境下进行,得到C0304杂相。两种方法反应过程的差异造成了Zm1-xCoxO纳米粉体中载流子输运特征的不同,从而造成磁学性能的差异。更多还原

【Abstract】 The rapid development of micro-nano technology gave birth to using electron’s spin to design for quantum devices, which is spintronics. In recent years, the transition metal-doped ZnO-based diluted magnetic semiconductor materials have shown an increasingly important research value in spintronics basic theory and applications of spintronic devices. The in-depth study on Co-doped ZnO diluted magnetic semiconductor nanopowder materials has significance in scientific and application value.This thesis is to study on the effect of process parameters and doping content on the structure and magnetic properties of Zn1-XCoXO nanopowders prepared by sol-gel calcine method and sol-gel auto-combustion method. The main contents and conclusions of the thesis are as follows.Preparing Zn1-XCoXO nanopowders using sol-gel calcine method is to study the effect of aging conditions and calcining temperature on structure and magnetic properties of Zn0.95Co0.05O nanopowders, and the effect of doping content on microstructure and magnetic properties of Zn1-XCoXO nanopowders. The results showed that the sol need a temperature of100℃, suitable for the aging time is3days; Zn0.95Co0.05O nano-powder calcination and calcination temperature was below700℃, there were Co3O4impurity phase peak, when calcined Co2+form again when the temperature reaches800℃, Co3O4decomposed into CoO solid solution into the ZnO lattice form Zn0.95Co0.05O single-phase; when the Co doping content and more than7%, calcined at800℃the nanometer powder Zn1-XCoXO Co3O4impurity phases; sol-gel calcine method prepared the Zn1-XCoXO of nano-powders of Co solid solubility of slightly more than5%. The show room docile magnetic powder calcined at800℃the Zn1-XCoXO nano and Co doping concentration increased, the nano-powder paramagnetic enhancement.Preparing Zn1-XCoXO nanopowders using sol-gel auto-combustion method is to study the effect of doping content and calcining temperature on structure and magnetic properties of Zn1-XCoXO nanopowders. The study found that slightly more than7%, the degree of solid solution of Co doping content reaches and exceeds 10%, the Co single sample quality; the Zn1-XCoXO nanopowders, heat treatment is subsequently calcined, nano Zn0.93Co0.07O Powders still pure phase Co doped Co elemental oxide content greater than or equal to10%of the samples generated Co3O4, the calcination temperature reaches800℃, a small amount of the powders of Zn0.9Co0.1O nm Co3O4again decomposition of Co2+form solid solution into the ZnO lattice. The sol-gel auto-combustion method prepared Zn0.93Co0.07O nano exhibit ferromagnetism at room temperature, but with the calcination temperature, reduced ferromagnetic and paramagnetic, when the calcination temperature of800℃, the sample showed only obvious paramagnetic magnetic transition is likely to be derived from the changes in carrier transport characteristics of the sample.Making a comparative study on Zn1-XCoXO nanopowders prepared by sol-gel calcine method and sol-gel auto-combustion method, it is can be found that due to the difference of the reaction process, the solid solubility of Co ions and the impurity phase in Zn1-XCoXO nanopowders prepared by two different methods are different from each other. Sol-gel auto-combustion rapidly response, likely to cause hypoxic environment, Co elemental impurity phase; sol-gel calcine is taken place in oxygen-rich environment, Co3O4impurity phase. The differences in the reaction of the two methods resulted in carrier transport characteristics which leads to the differences in magnetic properties of Zn1-XCoXO nanopowders prepared by two different methods.更多还原