We report on the fabrication of field emission microcathodes which use carbon nanotubes as the field emission source. The devices incorporated an integrated gate electrode in order to achieve truly low-voltage field emission. A single-mask, self-aligned technique was used to pattern the gate, insulator and catalyst for nanotube growth. Vertically-aligned carbon nanotubes were then grown inside the gated structure by plasma-enhanced chemical vapour deposition. Our self-aligned fabrication process ensured that the nanotubes were always centred with respect to the gate apertures (2 mu m diameter) over the entire device. In order to obtain reproducible emission characteristics and to avoid degradation of the device, it was necessary to operate the gate in a pulsed voltage mode with a low duty cycle. The field emission device exhibited an initial turn-on voltage of 9 V. After the first measurements, the turn-on voltage shifted to 15 V, and a peak current density of 0.6 mA cm~(-2) at 40 V was achieved, using a duty cycle of 0.5 percent.
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机译:我们报告了使用碳纳米管作为场发射源的场发射微阴极的制造。这些设备集成了集成的栅电极,以实现真正的低压场发射。使用单掩模自对准技术为纳米管生长的栅极,绝缘体和催化剂构图。然后通过等离子增强化学气相沉积法在门控结构内部生长垂直排列的碳纳米管。我们的自对准制造工艺确保了纳米管始终相对于整个器件上的栅极孔(直径2微米)居中。为了获得可再现的发射特性并避免器件退化,有必要以低占空比的脉冲电压模式操作栅极。场发射器件的初始导通电压为9V。在首次测量后,导通电压变为15 V,并且在40 V时达到0.6 mA cm〜(-2)的峰值电流密度,使用0.5%的占空比。
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