200 keV He+辐照改性锐钛矿TiO2薄膜初步研究

Preliminary Research on Modification of Anatase TiO2 Films after 200 keV He+ Irradiation

为研究锐钛矿TiO2薄膜经200 keV He+辐照改性后的结构、形貌和性能变化,并探索其变化机制,利用多弧离子镀技术制备一批具有统一工艺参数的锐钛矿TiO2薄膜,在室温环境下进行能量为200 keV,注量为1×1016ions/cm2、5×1016ions/cm2和1×1017ions/cm2的He+薄膜辐照实验。结合未辐照样品且经一系列表征可知,XRD、XPS结果显示辐照后薄膜相结构无明显变化,表面部分Ti4+转化为Ti3+,并出现表面吸附O2分子的情况;SEM、TEM、AFM结果显示辐照后表面部分Ti"液滴"因辐照生热过高而熔化,氦泡沿薄膜生长方向分布;经四探针电阻测量仪、紫外-可见分光度仪测量可知,因缺陷引入导致薄膜光吸收性能及电阻率提升;从表面接触角测量仪结果可知,薄膜表面亲水性得到了改善;纳米压痕仪测量结果显示,硬度及弹性模量随辐照先因缺陷、位错等引入而增加,后因氦脆现象而退化。

In order to investigate modification changes in structure, morphology and properties of anatase TiO2 films after He+irradiation, and explored the mechanism of the change, this paper prepared a batch of anatase TiO2 films with uniform process parameters by multi-arc ion plating technology, and carried out the He+film irradiation experiments at room temperature with energy of 200 keV and fluxes of 1×1016 ions/cm2, 5×1016 ions/cm2 and 1×1017 ions/cm2. Combining with the irradiated samples and through a series of characterization, XRD and XPS results showed that no obvious phase transformation after irradiation and some Ti4+ions were transformed to Ti3+ions and absorbed oxygen atoms were emerged on surface. SEM, TEM and AFM results showed that the Ti "droplets" on the surface after irradiation melt due to the excessive heat generated by irradiation, and the helium bubbles distribute along the growth direction of the film. Measurements by four-probe resistometer and ultraviolet-visible spectrophotometer showed that the optical absorption and resistivity of the films were improved due to the introduction of defects.The hydrophilicity of the film surface was improved according to the results of the surface contact angle measuring instrument. The results of nanoindentation showed that the hardness and modulus of elasticity increased with the introduction of defects and dislocations, and then degraded due to helium embrittlement.