作者：杨清华, 王焕平, 卫国英, 徐时清
作者单位：中国计量大学材料科学与工程学院材料分析测试中心, 浙江 杭州 310018
关键词：场发射扫描电镜;NaYF4纳米粉体;加速电压;工作距离
摘要：
合适的加速电压和工作距离对准确观察纳米粉体的形貌和粒径尺寸具有重要影响。以NaYF4纳米粉体为研究对象，探讨加速电压与工作距离的匹配性以及不同加速电压对电镜成像的影响。通过对比相同加速电压、不同工作距离下观察得到的电镜图片，得出只有当加速电压与特定的工作距离匹配时才能得到清晰度高的电镜图片，具体加速电压与工作距离的匹配值如下：1 kV（4 mm），5 kV（4 mm），10 kV（8 mm），15 kV（12 mm），20 kV（15 mm），25 kV（20 mm），30 kV（25 mm）。在合适的工作距离下，通过对比不同加速电压观察得到的电镜图片，得出随着加速电压的增加，电镜图片的清晰度呈现出先增强后减弱的趋势，当加速电压为20 kV时得到清晰度最佳的电镜图片。
Investigation on testing parameters of SEM for NaYF4 nano powders
YANG Qinghua, WANG Huanping, WEI Guoying, XU Shiqing
Testing Center of Materials, College of Material Science and Engineering, China Jiliang University, Hangzhou 310018, China
Abstract: The acceleration voltage (Vacc) and working distance (WD) have significant effects on the observation for the accurate morphology and particle sizes of nano powders. NaYF4 nano powders were used as samples, their microstructures were observed by the filed emission scanning electron microscope and the influences of accelerating voltage and working distance to the imaging were investigated systematically. Comparing the imagines under the same Vacc and different WD, it was confirmed that high quality imagines could only obtained under matching values between Vacc and WD. The details of the matching values are: 1 kV(4 mm), 5 kV(4 mm), 10 kV(8 mm), 15 kV(12 mm), 20 kV(15 mm), 25 kV(20 mm) and 30 kV(25 mm). While, comparing the imagines under different Vacc, it was indicated that with the increase in Vacc, the definition of the images was enhanced first and then deteriorated. The proper value was 20kV.
Keywords: field emission scanning microscope;NaYF4 nano powders;accelerating voltage;working distance
2016, 42(7): 127-130 收稿日期: 2015-10-18;收到修改稿日期: 2015-12-11
基金项目: 浙江省自然科学基金项目（LY15F050005）
作者简介: 杨清华(1986-),男,湖南江华县人,实验师,硕士,研究方向为扫描电镜的维护与显微检测。
参考文献
[1] ADILSON C D, CLAUDETE G R, MARCOS L S, et al. Chemical characterization, nano-particle mineralogy and particle size distribution of basalt dust wastes[J]. Science of The Total Environment,2016,539(1):560-565.
[2] ANGELICA C, FRANCESCO L, ROBERTO G, et al. Understanding the role of heavy ion-irradiation induced surface columnar nanostructures through FESEM imaging[J]. Physica C: Superconductivity,2010,470(19):914-917.
[3] 周莹,王虎,吴伟,等. 加速电压的选择对FESEM图像的影响[J]. 实验室研究与探索,2012,31(10):227-230.
[4] TERENCE A, SANDRA R, STEVE M, et al. Chapter 33-field emission scanning electron microscopy and visualization of the cell interior[J]. Cell Biology,2006(3):325-333.
[5] 周丽花. 纳米粉末的制备方法对扫描电镜成像的影响[J].中国测试,2012,8(5):15-17.
[6] 马原辉,陈学广,刘哲. 扫描电镜粉末样品的制备方法[J].实验室科学,2011,14(1):148-150.
[7] 肖媛,刘伟,汪艳,等. 生物样品的扫描电镜样品制样干燥方法[J]. 实验室研究与探索,2013,32(5):45-54.
[8] 曹惠,林美玉. 制样条件对介孔硅扫描电镜图片的影响[J].中国测试,2014,40(6):38-41.
[9] 曹惠. 导电性较差样品的扫描电镜优化观测条件[J]. 中国测试,2014,40(3):19-22.
[10] ENDO A, YAMADA M, KATAOKA S, et al. Direct observation of surface structure of mesoporous silica with low acceleration voltage FE-SEM[J]. Colloids and Surfaces A: Physicochem Eng Aspects,2010(357):11-16.
[11] PHIFER D, TUMA L, VYSTAVEL T, et al. Improving SEM imaging performance using beam deceleration[J]. Microscopy Today,2009(17):40-49.
[12] SARAKOVSKIS S, KRIEKE G. Upconversion luminescence in erbium doped transparent oxyfluoride glass ceramics containing hexagonal NaYF4 nanocrystals[J]. Journal of the European Ceramic Society,2015,35(13):3665-3671.
[13] CHEN H, LANG Y B, ZHAO D, et al. Enhanced high-order upconversion luminescence of hexagonal phase NaYF4:Yb3+, Tm3+ crystals coated with homogeneous shell[J]. Journal of Fluorine Chemistry,2015(174):70-74.
[14] ZHANG Y Y, WANG B T, PENG J, et al. Rare earth doped NaYF4 nanorods: Synthesis and up-conversion luminescence spanning deep-ultraviolet to near-infrared regions[J]. Optical Materials,2015(40):107-111.
[15] 徐柏森,杨静. 实用电镜技术[M]. 南京:东南大学出版社,2008:10-11.
[16] 华佳捷,刘紫微,林初城,等. 场发射扫描电镜中荷电现象研究[J]. 电子显微学报,2014(3):226-262.
