镧对真空沉积银纳米粒子细化作用的研究

Study of the Miniaturization Caused by Lanthanum on Silver Nanoparticles Prepared by Vacuum Deposition

用透射电子显微镜 (TEM)和X射线衍射 (XRD)等方法研究了稀土元素镧对真空蒸发沉积银纳米粒子的细化作用。实验表明 ,用镧预处理的基底 ,对真空蒸发沉积的银纳米粒子有细化作用 ,可使银纳米粒子的粒度由 2 0～ 30nm减小到约 1 0nm。镧对银纳米粒子的细化作用机理是 :基底吸附镧增强了其对银原子的等效吸附能和基底表面徙动激活能 ,使银纳米粒子在基底表面的徙动扩散运动受到削弱 ,进而减少了相互团聚。作者认为 ,掺入镧后的与镧相关的成分为非晶态 ,其对银纳米粒子的细化作用使银的XRD衍射峰消失。由Lewis -Campbell理论分析估算得到 ,镧的引入使基底表面徙动激活能增加约 0 0 5 8eV ,相应的基底原子吸附能增加约 0 0 8～ 0 42eV。

The miniaturization caused by lanthanum on silver nanoparticles prepared by vacuum deposition were studied with TEM and XRD. Experimental result showed that, with the effect of lanthanum, the size of the silver particle decreased from 20～30nm to 10nm. The reason was that the atomic adsorption energy and the activation energy for surface diffusion of the substrate were increase under the effect of lanthanum, thus the moving and coalescing of the nanoparticles of silver were decreased. The component related with lanthanum was non-crystal. The miniaturization caused the XRD peak of silver disappear based on the theory of Lewis-Campbell, the increase of activation energy for surface diffusion of the substrate was estimated to be 0.058 eV, and the increase of adsorption energy was estimated to be 0.08～0.42 eV.