场发射扫描电镜条件对几种特殊样品形貌的影响

Effect of field emission scanning electron microscopy conditions on the morphology of several special samples

以日立SU8220冷场扫描电镜为例,以静电纺丝、石墨烯、碳纳米管、镍钴材料、纤维素等为研究对象,研究了探头选择、加速电压等因素对样品形貌的影响。研究发现,U探头可以观察到较好的样品表面细节,L探头能够得到立体感良好的图像;高加速电压致使导电差样品荷电现象严重,无法得到高分辨率样品形貌,且容易掩盖极表面样品形貌;低加速电压能够抑制荷电现象,得到极表面样品形貌以及低衬度形貌,且对于观察不导电样品、热敏性样品有效果显著;镀膜能够有效解决样品荷电问题,但对于平整、孔径小样品,容易掩盖样品形貌。

By taking the cold field scanning electron microscope of Hitachi SU8220 as an example,the effects of probe selection and accelerating voltage on the morphology of the samples are studied with electrospinning,graphene,carbon nanotubes,nickel cobalt materials,cellulose,etc.It is found that the U probe can observe better surface details of the sample,and the L probe can get better stereoscopic image.The high acceleration voltage leads to the serious charge phenomenon of the sample with poor conductivity,which makes it impossible to obtain the high-resolution sample morphology and easy to mask the sample morphology on the electrode surface.The results show that the low acceleration voltage can suppress the charge phenomenon,and the morphology of the electrode surface and the low contrast morphology can be obtained,which has significant effect on the observation of non-conducting samples and heat sensitive samples.Coating can effectively solve the charge problem of the sample,but it is easy to cover up the sample morphology for flat and small aperture samples.