The adsorption of oxygen on the surfaces of (110) and (100) oriented tungsten single crystals

Hopkins, B.J.; Pender, K.R.

doi:10.1016/0039-6028(66)90058-6

Cited by 44 publications

(5 citation statements)

References 6 publications

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“…The oxygen-tungsten bond length determined here is consistent with the trend observed for c(2x2) and£(2x2) oxygen chemisorption on nickeL 8 ' 9 Given an experimentally measured 10 work function change of Acp =0.7 eV, we estimate the amount of charge transfer from tungsten to oxygen to be q/e = 4.4%, where e is the electron charge. Submillimeter photoconductivity in doped-Ge and -Si crystals has been investigated by Gershenzon and co-workers 1 * 2 using backward-wave tubes (BWT).…”

supporting

confidence: 85%

Very Shallow Trapping State in Doped Germanium

1975

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supporting

confidence: 85%

Very Shallow Trapping State in Doped Germanium

1975

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“…The value of 5.20 eV used here for the (1 10) plane is in agreement with many of the literature values (Hopkins and Pender 1966) although it should be pointed out that much of the field emission work indicates a value of about 6 eV or even higher (Plummer and Rhodin 1967, 1968, Engel and Gomer 1969.…”

Section: Work Function Measurementssupporting

confidence: 91%

Adsorption of uranium on tungsten single crystal planes

Collins

Blott

1971

J. Phys. D: Appl. Phys.

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Uranium adsorption on the (110), (112), (100), (111), (113) and (116) planes of tungsten field emitter substrates has been studied. Measurements of work function against coverage at 295 K, 950 K and 1120 K were found to be in good agreement with previous contact potential difference and photoelectric measurements. A Topping point dipole depolarization model has been used to determine dipole moments and effective adsorbate polarizabilities. This model is found to be only partially adequate in describing the adsorption process, deviation from the theory being most evident for the (100) plane.

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“…This value is lower than that of the cleaned and oxidized W surface (4,5 eV for clean W surface and 5,67 eV for oxidized W surface, respectively) and higher than it is suggested for the BaO covered tungsten surface (2,0-2,30 eV). This observation could be connected to the oxygen adsorption to the surface: from the literature it is well known that the adsorbed oxygen increases the work function at least by 2 eV [17][18][19].…”

Section: Resultsmentioning

confidence: 99%

Investigation of evolved layer structure of Ba-containing emission materials

Beck

Josepovits

Sneider³

2007

Per. Pol. Chem. Eng.

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The emission material in High Intensity Discharge (HID) lamps plays a significant role in lowering the electrode work function and thus the lamps' operating temperature. Bacontaining rare earth-and alkali earth tungstate materials are commonly used as cathode thermionic emission materials because of the production of high intensity discharge.The goal of this present work is to model a cathode tip surface evolved during sintering and to compare the physical and chemical properties of emission materials currently used in the industry. In order to achieve this goal, we investigated and compared the layer structure of Ba-Ca-and Ba-Y-containing emission materials evolved on polycrystalline tungsten foils. Simultaneously, the tendency of the work function was also monitored as a function of Ba/BaO layer thickness. The Ba coverage of cathode is one of the most important factors during the lifetime of HID lamps. The initial Ba diffusion was also examined. We also proposed a layer model, valuable for the structures occurring during the operation of lamps.The chemical composition of the flat samples was analysed by X-ray Photoelectron Spectroscopy (XPS) and the electron emission properties by Work Function Spectroscopy (WFS).

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The adsorption of oxygen on the surfaces of (110) and (100) oriented tungsten single crystals

Cited by 44 publications

References 6 publications

Very Shallow Trapping State in Doped Germanium

Very Shallow Trapping State in Doped Germanium

Adsorption of uranium on tungsten single crystal planes

Investigation of evolved layer structure of Ba-containing emission materials

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