Ni∶MgO纳米复合薄膜的结构及其光学性质研究

Study on the structure and optical properties of Ni∶MgO nanocomposite films

采用脉冲激光气相沉积技术,将Ni纳米颗粒嵌埋在MgO薄膜中,形成Ni∶MgO纳米复合薄膜(Ni NCs∶MgO)。分别采用高分辨X射线衍射技术和紫外-可见吸收光谱详细研究了薄膜的晶体结构及光学性质。HRXRD结果表明MgO薄膜和Ni纳米颗粒都沿着(200)方向生长;由于Ni纳米颗粒的嵌埋,导致MgO基质发生了晶格畸变,从而使得MgO基质的晶格常数发生改变;晶格畸变也导致MgO的衍射峰被展宽;Ni的含量与其颗粒尺寸随着沉积Ni的激光脉冲数的增加而增加。紫外-可见吸收光谱的分析结果表明在190～600nm波长范围内薄膜的吸收峰是Ni纳米颗粒的表面等离激元共振吸收峰;随着沉积Ni激光脉冲数的增加,单个吸收峰强度增强的同时还发生了红移;当沉积Ni的激光脉冲数从200增加到250时,吸收峰发生劈裂。

Eptaxial MgO films with embedded metallic Ni nanocrystal （Ni NCs ： MgO） multilayer films were successfully fabricated on MgO substrate by pulsed laser deposition （PLD） method. High resolution X-ray diffraction （HRXRD） and UV-Visible absorption spectra were employed to analyze the structure and optical properties of Ni NCs ： MgO films respectively. HRXRD results showed that the MgO substrate and Ni metallic particles all were growing along with the （200） direction. The embedding of Ni NCs caused lattice distortion of MgO films. As a result, the lattice of MgO changed and the diffraction peaks of MgO were broadening. The account and the size of Ni particles increased with the increase of the laser pulse numbers of Ni. According to the UV-Vis absorption spectra, the Ni NCs surface plasmon resonance absorption peaks were observed in the wavelength range of 190-600nm. With the increase of laser pulse numbers of Ni, the intensity of each single absorption peak increased at the same time with red-shifting. When laser pulse numbers of Ni increased from 200 to 250, one absorption peak split.