碳纳米管/金刚石复合材料的场发射特性

采用微波烧结方法制备了碳纳米管/金刚石复合材料。将碳纳米管和纳米金刚石粉末混合后研磨压片,然后在微波等离子气相沉积系统中采用微波烧结。利用扫描电镜对复合材料的表面形貌和微观结构进行了分析,结果显示碳纳米管比较均匀地分散于复合材料中,并在表面形成了发射微尖。利用二极管结构在动态真空室中对复合材料的场发射特性进行了研究,复合材料有较好的场发射特性,电流密度接近15mA/cm2。

Field Emission Property of Carbon Nanotubes/Diamond Composite

In order to achieve good stability of field emission as well as high current density, various carbon nanotube-based composites were developed. Here, carbon nanotubes/diamond composites were prepared by microwave sintering method. The carbon nanotubes were dispersed through the composite by thoroughly grin-ding the mixtures. Then, the mixtures were pressed into sheets and sintered by microwave in a microwave plasma chemical vapor deposition system. Morphologies and structural characteristics of composites were cha-racteriozed by scanning electron microscopy. The analytic results demonstrated that the carbon nanotubes are uniformly embedded in composite and formed emission tip. The field emission properties of carbon nanotubes/diamond composite cathodes were also measured in a high vacuum chamber at room temperature using a typical planar diode configuration. The measurement of field emission properties were carried out in a diode structure, wherein the sample acted as the cathode and a stainless-steel cylinder with a diameter of 2.1 mm served as the anode. The distance between the cathode and anode was maintained at 300 μm. The measurement results showed that the field emission of carbon nanotubes/diamond composite is enhanced and the high current density is obtained. A high emission current density value of about 15 V/cm2 is obtained. The results revealed that microwave sintering process is an effective and simple method to synthesize carbon nanotubes/diamond composite.