Secondary electron emission from magnesium oxide on multiwalled carbon nanotubes

Abstract

We have investigated effects of electric fields on the yield of secondary electron emission ͑SEE͒ from the primary electron bombardment on magnesium oxide ͑MgO͒ covering vertically grown multiwalled carbon nanotubes ͑MWCNTs͒. We observe that the yield of SEE increases up to at least 22 000 at a special condition. The strong local field generated by the sharp tip of vertically grown MWCNTs accelerates secondary electrons generated by primary electrons. This eventually gives rise to so called Townsend avalanche effect, generating huge number of secondary electrons in a MgO film. Emission mechanism for such a high SEE will be further discussed with energy spectrum analysis.

Unusual secondary electron emission behavior in carbon nanotube forests

“…These studies reported SE emission yield from various samples under different conditions. For example, maximum electron yield from MgO-coated MWNTs was reported to be in the range of 21-22,000 from different MgO/MWNT samples (Kim et al 2002;Lee et al 2009;Yi et al 2001). However, there is still much to be learnt about the SE emission behavior of bare CNTs.…”

“…SE emission also plays a very important role in the imaging of CNTs (Brintlinger et al 2002;Finnie et al 2008;Homma et al 2004;Wong et al 2006), yet only a few reports exist in the literature on SE emission from CNTs. Electron yield from multi-walled carbon nanotube (MWNT) carpets (very wide forests with macroscopic dimensions) coated with different materials such as MgO, CsI and ZnO has mainly been reported so far (Huang et al 2006;Kim et al 2002;Lee et al 2009;Yi et al 2001). These studies reported SE emission yield from various samples under different conditions.…”

“…Carbon nanotubes (CNTs) are considered promising candidates for electron multipliers because of their excellent electron emission properties. They have been shown to enable robust, stable, low-voltage and highbrightness electron emitters (De Jonge and Bonard 2004;De Jonge et al 2005;Hu et al 2001;Yaghoobi and Nojeh 2007) and high electron gain (Kim et al 2002;Nojeh et al 2004;Yi et al 2001). SE emission also plays a very important role in the imaging of CNTs (Brintlinger et al 2002;Finnie et al 2008;Homma et al 2004;Wong et al 2006), yet only a few reports exist in the literature on SE emission from CNTs.…”

“…The schematic of the experimental apparatus is shown in Figure 2. We followed a procedure similar to that used by others for the measurement of total electron yield (TEY) from various materials (Kim et al 2002;Lee et al 2009;Yi et al 2001), as well as for SE and BSE coefficients (Huang et al 2006;Sim and White 2005).…”

Studies on Electrical and Retention Enhancement Properties of Metal-Ferroelectric-Insulator-Semiconductor with Radical Irradiation Treatments

“…The Ferroelectric SBT films gather many advantage in characteristics over other ferroelectric compounds, for application in ferroelectric memory which include a fatigue-free behavior, good retention properties and low leakage currents [Paz de Araujo, C.A., etc., (1995)]. But they require a high temperature annealing (700 o C~800 o C) for crystallization that is main cause of constituent-element diffusion from the ferroelectric film into and the insulator layer in Pt/SBT/SiO 2 /n-Si MFIS structure [Kim, W. S., (2002), Li, Y., [Kim, W. S., etc., (2002), Li, Y., etc., (2007), Aguilar, G. G., etc., (2006)]. Therefore, Pt/SBT/SiO 2 /n-Si MFIS structure could not give good characteristics without any treatment processes and be used for any ferroelectric memory devices.…”