Work function of MgO single crystals from ion-induced secondary electron emission coefficient

Ajou University, Sŏul, Seoul, South Korea
Journal of Applied Physics (Impact Factor: 2.18). 07/2003; 94(1). DOI: 10.1063/1.1581376


The work functions ϕω of MgO single crystals with its respective orientation (111), (200), and (220) have been investigated from their ion-induced secondary electron emission coefficient Γ, respectively, using various ions with different ionization energies in a Γ-focused ion beam system. The work function ϕω for MgO single crystal with (111) orientation has the lowest value, 4.22 eV, whereas it is 4.94 eV for (200) and the highest value is 5.07 eV for (220). These work functions of MgO single crystals can explain the nonzero values of the ion-induced secondary electron emission coefficient Γ for Xe+ ions, whose ionization energy is 12.13 eV.

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    • "The presence of pure Mg on the surface of the Mg:Ag alloy layer is likely related to the difference in boiling points of Ag (T Ag-boiling =2435 K) and Mg (T Mg-boiling =1363 K): Due to the much lower boiling point of Mg, Mg vapors will be condensed last after the deposition process is finished (shutter closed) resulting in a Mg enriched front surface. The last value of 4.42 eV is similar to that of a MgO single crystal with (111) orientation [4] suggesting that MgO is formed on the front side. This finding is in good agreement with the observation of the O KLL Auger electron peak in the XPS overview spectra indicating the presence of oxidized Mg 0 . "
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    Full-text · Article · Dec 2012 · Energy Procedia
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    • "More drastic increase in the driving voltage is also shown for that Fe/MgO(001)-based TOLED. The large driving voltage could be attributed to the larger work function of the MgO(001) layer (4.94 eV) [17] than that of Al (4.1 eV) [18] or poly-Fe (4.5 eV) [18]. Additionally, the effect of surface potential at the MgO(001)/CuPc interface could not be negligible. "
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    Full-text · Article · Nov 2012 · Nanoscale Research Letters
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    • "The work function is derived from the value of the xaxis at the peak point, which is 3.61 eV for the conventional MgO protective layer and 3.22 eV for the proposed MgO protective layer. As a result, when the Au nanoparticles are inserted, the work function of the proposed structure falls by about 0.4 eV, and the SEE property is consequently enhanced [11], [17]. In addition, the nonflat-surface morphology, which is induced by the nanometer-scale bumps, is expected to enhance the SEE property [18]. "
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    ABSTRACT: This paper proposes a modified alternating current plasma display panel (PDP) in which gold nanoparticles are incorporated into a bare MgO layer to enhance the performance of the protective layer. The proposed structure's ion-induced secondary electron yield, which is expressed in a gamma value ( value) is greater than that of a bare MgO layer; as a result, the operating voltage decreases by 10 V to 20 V. The integration of emitted infrared (IR) light and the power density consumed by the discharge current are both increased, but the ratio of increment is greater for the case of the IR light. Consequently, IR efficacy is increased. The IR response time of the sustain discharge and the address discharge time lag are reduced by the enhanced wall charge accumulation characteristic and the exoelectron emission property. The results of ultraviolet photoelectron spectroscopy show that a MgO layer with Au nanoparticles has a lower work function than a conventional bare MgO layer. Furthermore, the structure that is not flattened by nanoparticles seems to enhance the secondary electron emission property of the MgO protective layer. Consequently, the value is enhanced by the two reasons previously mentioned.
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