采用电泳法在Si基底上沉积了碳纳米管(CNTs)薄膜, 并利用Ar微波等离子体对CNTs薄膜进行了改性处理, 研究了改性前后CNTs的微观结构和场发射性能. 高分辨透射电子显微镜(HRTEM)和拉曼光谱的表征结果表明, 等离子体改性明显改变了CNTs的微观结构, 形成了大量的管壁结构缺陷、纳米级突起和“针形”尖端; 场发射测试结果表明, CNTs经Ar等离子体改性处理后开启电场较改性前?略有增大, 等离子体改性10min的CNTs薄膜表现出最佳的场发射J-E特性, 阈值电场由改性前的3.12V/μm降低到2.54V/μm, 当电场强度为3.3V/μm时, 场发射电流密度由改性前的18.4mA/cm2增大到60.7mA/cm2. 对Ar微波等离子体改性增强CNTs薄膜场发射性能的机理进行了分析.
The carbon nanotubes (CNTs) film was prepared on Si substrate by electrophoretic deposition (EPD) and treated by Ar microwave plasma. The microstructure and field emission properties of the as-prepared CNTs films before and after treatment were investigated. High-resolution transmission electron microscope (HRTEM) and Raman spectroscope reveal the microstructural changes of CNTs after the plasma treatment as evidence of the appearance of a large amount of structural defects, the sticking with nanometer size and “needle-like” tips. The field emission measurements indicate that the turn on electric field is increased slightly after treatment. The sample treated by Ar plasma for 10min shows the best field emission J-E property. Compared to that of untreated sample, the threshold field of the CNTs film treated for 10min decreases from 3.12V/μm to 2.54V/μm. And after plasma treatment, the emission current density at applied electric field of 3.3V/μm increase from 18.4mA/cm2 to 60.7mA/cm2. The mechanism of variation of field emission properties after plasma treatment is discussed.
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