Fuming Mao

Study of a micro chamber quadrupole mass spectrometer

Copyright @ 2008 American Vacuum Society / American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Vacuum Science and Technology Part A: International Journal Devoted to Vacuum, Surfaces, and Films, 26(2), Article number 239 and may be found at http://scitation.aip.org/content/avs/journal/jvsta/26/2/10.1116/1.2827512.

Residual gas analysis based on carbon nanotube field emission display

The authors measured the residual gas spectrum of a field emission display (FED) with carbon nanotube (CNT) emitters and found that the main residual gases inside a sealed CNT FED, containing an evaporated Ba getter, are H2, CH4, CO, Ar, and CO2, all of which are typical residual gases of electronic vacuum tubes. Additionally they also measured the electron stimulated desorption of gases by operating their field emission devices.

Effect of CO on the field emission properties of zinc oxide

Zinc oxide is a wide band gap semiconductor (WBGS). Its band bending, which usually favors field emission by lowering surface barrier and bringing more electrons to the bottom of conduction band, can be quite dramatic under high field. In the last few years, different kinds of ZnO nano-materials has been synthesized and applied as the cathode materials for field emission. For better application of ZnO in commercial field emission devices, long-term current stability is one of the most important aspects to be ensured. So in this paper, the field emission behavior of screen printing tetrapod ZnO will be studied by exposing to CO, which is the main residual gas in sealed tetrapod ZnO (T-ZnO) field emission device.

Ambient gas properties of field emission devices

In order to study whether the ambient gases affect the emission current stability of the cathode, the cathode should be the same one. In addition, the working condition should be kept constant except the ambient gas condition, so that other factors, which may also lead to the emission current degradation of the cathode, can be avoided. Only the influence from the residual gases will be concerned. For this consideration, an experimental system was set up, as shown in Fig. 1. It consisted of a vacuum system with a quadrupole mass spectrometer (QMS) and FE device opening set to introduce the residual gases inside the FE device into the analysis system.

Enhanced field emission of tetrapod zinc oxide in methane

Tetrapod zinc oxide (T-ZnO), being a kind of nano-scale material, has a large specific surface area and high surface binding energy, which will make it sensitive to ambient gases; hence, the field emission (FE) properties of this ZnO nanomaterial will be influenced by gas adsorption. The effect of methane on the field emission of T-ZnO emitters was investigated. It was found that CH4 enhanced the field emission substantially. By curve fitting we are able to describe the experimental results adequately as a function of the methane pressure. The increase of the field emission is caused by a lower work function of the ZnO-emitters.

Residual Gas Analysis based on CNT-FED

We studied the residual gases inside field emission displays (FEDs) with carbon nanotube(CNTs) emitters, and found that the main residual gases inside sealed CNT-FEDs are Ar and CO, both of which are typical residual gases inside electronic vacuum tubes

The Outgassing Characteristics of CNT and ZnO Cathodes

The true outgassing from cathodes is often masked by the production of gases released by phosphors in field emission displays (FEDs). The outgassing characteristics of CNT cathode and ZnO cathode for application in FEDs are presented. Quadropole mass spectrometer (QMS) has been used to measure the outgassing characteristics from carefully prepared samples of CNT and ZnO cathodes in ultra-high vacuum (UHV) system. We observe that the outgassing rate of ZnO cathode is much lower than it of CNT cathode due to its solid structure, but they have the similar outgassing. It has been shown that the main components of released gases are water vapor, carbon monoxide, carbon dioxide and oxygen

Outgassing of FED Under Operation

In this paper, the outgassing of field emission display (FED) was studied using vacuum chamber and FED panel. The gas was measured with a quadrupole mass spectrometer (QMS), and the mean gas outgassed from the FED panel is CO when the device is working at about 1000V