The Preparation Of Carbon Nanotube Array With Constant Current Emission

Since the discovery of carbon nanotubes, the unique structure and excellent field emission performance makes it widely used, carbon nanotubes are considered to be the most ideal material for field emission. But in the experiment, the local carbon nanotube maybe appear overheat by too high current in the process of field emission,leading to the contact between substrate and carbon nanotubes melting and vacuum breakdown. In this paper, we designed a model of carbon nanotubes with constant emission current to avoid “over-emission”. According to this model, carbon nanotubes were grown on the anode of constant current diode arrays to avoid the “over-emission”of carbon nanotubes with limitation of the maximum current by the constant current diode array.This paper includes the following contents:(1)The model design of the carbon nanotube array with constant emission current.We designed the carbon nanotube array with constant emission current to solve this problem after the analysis of the spark phenomenon,(2) The design and fabrication of constant current diode. We designed the constant current diode that meet our requirements, and prepared the constant current diode through semiconductor technology. Then we made a detailed analysis for the effects to the constant current diode performance caused by the process of oxidation, isolation layer, the gate, source and drain electrodes, electrode contact hole and etc. At last, we made a test for the performance of constant current diode.(3) The preparation of carbon nanotube array. By using Cu/Al/Fe as catalyst structure array, we grew the carbon nanotube array using microwave plasma chemical vapor deposition(MWPCVD). We can change the size of the catalyst arrays by lithography process and then control the size and arrangement of carbon nanotube array. At last, we achieved the oriented carbon nanotube arrays on the anode of constant current diode successfully.(4) The field emission test. The I-V characteristics of the carbon nanotube array grew on the anode of the constant current diode were test under UHV system.