氧化钒薄膜的掺杂及电阻突变特性研究

【作者】 赵力丁；

【导师】 吴志明；

【作者基本信息】 电子科技大学 ， 材料物理与化学， 2006， 硕士

【摘要】 VO2是一种相变型金属氧化物,随温度的升高,在相变温度（Tc=68℃）发生从低温单斜结构向高温四方金红石结构的转变,同时,伴随着电阻率和红外光透过率的突变。这一特有的性质使VO₂在众多领域具有好的应用前景。从上世纪八十年代开始的对VO₂的掺杂研究表明:掺杂能明显改变VO₂薄膜的相变温度,进而影响其光电性能。因为VO₂的应用中绝大多数都要求其相变温度接近室温,所以是否可以通过掺杂手段使其相变温度降至室温附近,并使掺杂薄膜的性能发生有利于应用要求的相应变化是近来VO₂薄膜掺杂改性的研究主题。针对VO₂薄膜的研究发展动向和实践的需要,本论文主要在掺入不同价态的过渡金属杂质(Zr4+以及Cr³⁺对VO₂薄膜性能产生的影响等方面进行了基础研究。具体而言,本论文从事的主要工作如下:（1）本文首先利用无机溶胶-凝胶法制备了含有4价锆的VO₂薄膜,通过改变掺杂浓度,测定了在不同掺杂浓度下VO₂薄膜的电阻-温度关系曲线。在此基础上,本文进一步探讨了掺杂浓度与VO₂薄膜相变温度、电阻突变数量级以及热滞宽度的关系。实验结果表明:随Zr含量的增加,VO₂薄膜的半导体-金属转变温度和电阻突变数量级呈线性下降,同时,随掺杂量的增加,VO₂薄膜的热滞宽度的变化规律是先减小后增大。（2）本文以掺锆为例,探讨了不同的真空退火温度对VO₂薄膜的相变温度、电阻突变数量级以及热滞宽度有何影响。通过对比不同退火温度下的测试结果可知:经450℃退火后的掺杂VO₂薄膜与其它退火温度所得的VO₂薄膜相比,具有较低的相变温度以及较为明显的电阻突变数量级。因此,在350～500℃之间,VO₂薄膜的最佳退火温度为450℃。（3）最后,本文采用无机溶胶-凝胶法制备了含有3价铬的VO₂薄膜,研究了其掺杂量与电阻突变特性的关系。经测试发现,在开始阶段,随Cr³⁺浓度地增加,VO₂薄膜的相变温度降低,当Cr³⁺浓度达到一定值之后,其相变温度随浓度地升高而迅速上升。同时,VO₂薄膜的电阻突变量随Cr³⁺浓度地增加而减小。而热滞宽度的变化规律是先增大后减小。更多还原

【Abstract】 VO₂ is a typical thermochromic material. With the increase of temperature, the semiconductor-to-metal transition will occur at 68°C; with the abrupt change of VO₂ crystal structure, electrical resistance and optical index of refraction transmissivity and reflectivity will change, which results in great application potentials in many fields. Since 1980s research about doped VO₂ matrix has shown that doping could alter the phase transition temperature of VO₂ thin film, and as a result, influence on its optical and electrical properties. Due to the requirement of VO₂ phase transition temperature near to room temperature in practical application, whether phase transition temperature of VO₂ could be decreased to the room temperature by doping has become the hot topic relevant to VO₂ film property modification in recent years.According to the development trend and practical need of VO₂ thin film, in this study, some basic research in the field of VO₂ film property modification by doping with transitional metals at various valences such as Zr⁴⁺ and Cr³⁺ has been focused on. Specifically, the architecture of this dissertation is as below:At first, using inorganic sol-gel method VO₂ thin films doped by Zr⁴⁺ ion were prepared. By varying the doping concentration of Zr⁴⁺, corresponding resistance-temperature curves were measured. On the other hand, relationship between doping concentration, phase transition temperature, magnitude of resistance change and hysteresis width was investigated. Results show that the increase of semiconductor-metal phase transition temperature and the decrease extent of resistance is linear to Zr⁴⁺ doping content, while the hysteresis width of VO₂ thin film fluctuates with Zr⁴⁺ doping content.Then, the effect of vacuum annealing temperature on VO₂ thin film phase transition temperature, magnitude of resistance change and hysteresis width by doping Zr⁴⁺ was discussed. Compared with testing results at different annealing temperatures ranging from 350 to 500°C, it was found that VO₂ film annealed at 450°C exhibits lower phase transition temperature and significant resistance change. Therefore, the optimum annealing temperature for VO₂ film of 450°C was achieved.更多还原