Alkali vapour pressure variations during Na2KSb(Cs) photocathode synthesis

Erjavec, Bojan

doi:10.1016/0042-207x(94)90263-1

Cited by 15 publications

(12 citation statements)

References 6 publications

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“…The characteristics such as the photon absorption and feasible work function make these compounds suitable candidates for electron emission devices [3][4][5]. On the experimental side, high attention to alkali antimonides has been paid for exploration of the important electrical and optical properties for their use in technological applications [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Structural, elastic, electronic and optical properties of bi-alkali antimonides

Murtaza

Ullah

et al. 2016

Bull Mater Sci

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The structural parameters, elastic constants, electronic and optical properties of the bi-alkali antimonides (Na 2 KSb, Na 2 RbSb, Na 2 CsSb, K 2 RbSb, K 2 CsSb and Rb 2 CsSb) were calculated using state-of-the-art density functional theory. Different exchange-correlation potentials were adopted to predict the physical properties of these compounds. The calculated structural parameters are found in good agreement with the available experimental and theoretical results. All the compounds are mechanically stable. The compounds Na 2 KSb, K 2 RbSb, K 2 CsSb and Rb 2 CsSb have direct bandgaps, in which chemical bonding among the cations and anions is mainly ionic. Furthermore, the optical properties of these compounds are described in detail in terms of the dielectric function, refractive index, reflectivity, optical conductivity and absorption coefficient.

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Section: Introductionmentioning

confidence: 99%

Structural, elastic, electronic and optical properties of bi-alkali antimonides

Murtaza

Ullah

et al. 2016

Bull Mater Sci

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“…Since the earlier investigation [1][2][3][4][5][6][7][8], alkali antimonide compounds have attracted much attention and extensive experimental studies on their properties have been carried out [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Optical properties of the alkali antimonide semiconductors , , and

Kalarasse

Bennecer

Kalarasse

2010

Journal of Physics and Chemistry of Solids

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“…The leakage currents are only weakly dependent upon temperature so their activation energies may be as low as ∼0.1 to 0.2 eV. (2) An alternative option, which may be relevant for the S20 cathodes, is that because the material is not homogeneous, and may be comprised of two compounds [10][11][12][13], different grains have different work functions. If there are two similar work functions then the measured data will show some curvature and the 'knee' between the regions where each type dominates will be sensitive to the mixture within a particular PM tube.…”

Section: Dark Current Theorymentioning

confidence: 99%

“…Cathode composition and structure are crucial factors and for this wavelength range many manufacturers use a multialkali composition, often termed an S20 cathode [6][7][8][9]. Idealized models of the cathode assume it is of a homogeneous stoichiometric composition comprising two alkali phases of Na 2 KSb and K 2 CsSb [10][11][12][13]. The obvious variations in performance and methods of deposition used by different manufacturers suggests that this may be an idealized model and in reality the methods of cathode deposition are non-uniform in thickness and the deposition rate across the cathode window and the material is likely to include layering as well as local compositional variations.…”

Section: Introductionmentioning

confidence: 99%

Dark current and sensitivity measurements for structured S20 photocathodes

Wang

Downey

Harmer

et al. 2006

J. Phys. D: Appl. Phys.

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Measurements of the temperature dependence of the dark current for standard commercial photomultipliers with multialkali photocathodes (type S20) have been contrasted with data from new prototype tubes with greatly enhanced long wavelength performance. The analyses suggest that for the larger structures part of the cathode is closer to a bialkali composition. This reduces the activation energy of the dark current from ∼1.1 eV for normal S20 cathodes down to ∼0.8 eV. Many tubes show a lower activation energy component near 0.6 eV which may represent a sensitization process from monolayers of molecular oxygen. Similarly, monolayers of water can play a significant role, but do so by reducing cathode sensitivity. Several tubes display a sharp transition in gain at the limiting temperature for water desorption (i.e. a sublimation transition). The commercial structured cathodes can show evidence for up to 70% improvements in quantum efficiency by operation at low temperature which can be immediately exploited. Prototype tubes with greatly improved performance were studied but for very small area illumination spots there can be problems of local variations in gain and wavelength response across the structural features of pyramidal modified cathode windows. Overall the data suggest that not only is improved performance already available with existing photomultiplier tubes but also with structured photocathode windows, and/or the introduction of surface ‘defects’ in the window, even further improvements are feasible.

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Alkali vapour pressure variations during Na2KSb(Cs) photocathode synthesis

Cited by 15 publications

References 6 publications

Structural, elastic, electronic and optical properties of bi-alkali antimonides

Structural, elastic, electronic and optical properties of bi-alkali antimonides

Optical properties of the alkali antimonide semiconductors , , and

Dark current and sensitivity measurements for structured S20 photocathodes

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