To selectively control the electrical resistance, thin films of TiO₂ were irradiated with a YVO₄ third-harmonic generation pulse laser in various power conditions. It was observed that when the laser power was less than 0.26 W, the electrical resistance of thin films decreased with the increase in laser power, whereas when the laser power was more than 0.26 W, the electrical resistance increased as the laser power increases. The minimum electrical resistance of the irradiated thin film was found to be four orders of magnitude lower than that of the unirradiated thin film. X-ray absorption fine structure analysis revealed that the valence of Ti ions in the thin films was reduced after laser irradiation, indicating the formation of oxygen vacancies with electron doping. The cross-sectional observation by a scanning electron microscope revealed that high laser power irradiation caused the thin films to become porous, and the percolation theory explains the origin of the increase in electrical resistance with developing porous structure. We propose a phase diagram to completely explain the relationship between electrical resistance and laser power, which supply a guideline on laser modification in TiO₂ electrical resistance.

中文翻译：

---

了解 YVO4 三次谐波产生脉冲激光照射 TiO2 薄膜的电阻变化

为了选择性地控制电阻，用 YVO _{4辐照 TiO 2}薄膜各种功率条件下的三次谐波产生脉冲激光器。观察到当激光功率小于0.26 W时，薄膜的电阻随着激光功率的增加而降低，而当激光功率大于0.26 W时，薄膜的电阻随着激光功率的增加而增加。经辐照薄膜的最小电阻被发现比未辐照薄膜低四个数量级。X射线吸收精细结构分析表明，激光照射后薄膜中Ti离子的化合价降低，表明电子掺杂形成了氧空位。通过扫描电子显微镜的横截面观察表明，高激光功率照射导致薄膜变得多孔，渗流理论解释了随着多孔结构的发展电阻增加的原因。我们提出了一个相图来完整解释电阻和激光功率之间的关系，这为二氧化钛的激光改性提供了指导₂电阻。