金刚石/银复合材料:制备、电泳沉积及场发射性能研究

Diamond/Ag Composites:Synthesis,Electrophoretic Deposition and Field Emission Properties

采用化学镀银的方法,制备了银包覆的金刚石复合材料,并利用场发射扫描电子显微镜(FESEM)、X射线衍射仪(XRD)和拉曼(Raman)光谱对样品的形貌和微结构进行了表征。利用电泳沉积的方法,制备了均匀的金刚石/银复合材料薄膜,场发射测试结果表明,在22 V/μm的电场下,金刚石/银复合材料的发射电流密度可达23.7μA/cm2;而在26 V/μm的电场下,高压金刚石薄膜的发射电流密度仅为0.2μA/cm2。与高压金刚石薄膜的场发射结果相比,金刚石/银复合材料的场发射性能有明显的提高。银的存在使银与金刚石界面处形成电子发射区,在外加电场作用下,该区域电子优先隧穿表面势垒逸出到真空,形成场致电子发射。

Using chemical plating method, diamonds coated with Ag composites were synthesized. The morphology and microstructure of diamonds/Ag composites were characterized by field emission scanning electron microscope （FESEM）, X-ray diffraction fXRD） and Raman spectroscope, respectively. Moreover, diamonds/Ag composites films was also prepared by electrophoretic deposition method. The results of field emission showed that the emission current density of diamonds/Ag composites films can be up to 23.7 μA/cm^2 at the applied electric field of 22 V/μm. However, the emission current density of high-pressure diamonds films is only 0. 2 μA/cm^2 at the applied electric field of 26 V/μm. Compared with the field emission results of high-pressure diamond films, it can be found that diamonds/Ag composites have more superior field emission properties. The presence of Ag forms the electron emission area between the interface of Ag and diamonds. Therefore, with the effect of applied electric field, the electrons in this area priorly emit into vacuum and form field electron emission.