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研究了定向生长的多壁碳纳米管薄膜场致发射的距离敏感特性,以改进现有场发射传感器中硅及金属针尖的性能。化学气相沉积方法制备的多壁碳纳米管薄膜表现出良好的尖端放电特性,其开启电场可至1.42 V/μm,阈值电场可至2.22 V/μm,通过计算得到的尖端电场增强因子可至4 034以上。随着发射间距的增加,场致发射电流非线性地降低,发射电流对发射间距的最大变化率为0.018 8μA/μm。通过拟合分析发现,场致发射电流随发射间距的变化基本符合Fow ler-N ordhe im关系,该特性可作为碳纳米管场致发射传感器的基本原理用于位移的检测。
The distance-sensitive properties of field-grown multi-walled carbon nanotube films with directional growth were studied to improve the performance of silicon and metal tips in field-emission sensors. The multi-walled carbon nanotube films prepared by chemical vapor deposition show good tip discharge characteristics with an on-field of 1.42 V / μm and a threshold electric field of 2.22 V / μm. The calculated electric field enhancement factor can be up to 4 034 above. With the increase of the emission pitch, the field emission current decreases nonlinearly, and the maximum change rate of the emission current to the emission pitch is 0.018 8μA / μm. The fitting analysis shows that the variation of the field emission current with the emission pitch basically accords with the Fowler-Nordheim relationship, which can be used as the basic principle of the carbon nanotube field emission sensor for displacement detection.