Fowler plots

Figure 7. Normalized photoresponses yield spectra for WOs in 1N HsSO The data are taken in order of decreasing negative potential at the potentials indicated. All of the currents are cathodic. The insert shows Fowler plots used to determine the photoemission threshold at each potential.

Fig. 14. (a) Plot of absorption data for the anodic oxide film on bismuth illustrating the determination of the band gap of the oxide, (b) Fowler plot of the cathodic photocurrent data below 2.8 eV showing the threshold intercept at 1.4 eV. (Reproduced with permission from ref. 29.) (c) Origin of the low-energy cathodic photocurrent response at oxide-coated electrodes. If the oxide is effectively insulating, the barrier height for photoemission is half the band gap. 

Fig. 15. Fowler plot of the cathodic photocurrent for lead anodised in 5.0 mol dm 3 H2S04 showing the threshold intercept at 1 eV. (Data taken from ref. 18.)...

Figure 5. Fowler plots of the photocurrent data for (1) anodic photocurrent and (2) cathodic photocurrent of the PANIfilm on ordered Au/p-ATP substrate in 0.05MK3Fe(CN)e/K4Fe(CN)e aqueous solution. Extrapolated photocurrent onsets indimte the energy barrier difference between the Fermi level of metallic region and the conduction band (cathodic photocurrent) or the valence band (anodic photocurrent) of semiconducting region in PANI film.

Photoelectric injection of electrons in solid rare gases was employed for the determination of the energy of the electronic conduction level, Vq, in solid Ar, Kr, and Xe. In Figure 2 normalized photocurrents are shown as a function of the photon energy in the form of Fowler plots. From the intercepts Vq values were obtained which are... 

Figure 2 Fowler plots of the photoelectron currents from a gold cathode in vacuum, solid and liquid Ar, Kr, Xe. (Redrawn from the data of von Zdrojewski, W., Rabe, J.G., and Schmidt, W.F., Z. Naturforsch., 35a, 672,1980.)...

Fokker-Planck dynamics, 55 equation, 58 Fowler plot, 241 Functional integration, 81... 

As in the case of metal electrodes, photoemission yield measurements can be expressed in empirical Fowler plots. ... 

Fig. 13. Electric-field dependence of the emission current obtained for a carefully aligned MWCNT film [38], Inset Fowler-Nordheim plot, where y is the field-enhancement factor.

The standard method for treating field-emission data is to make a plot of the logarithm of field-emission current In / versus MV or 1/F, then fit the data points with a straight line. This plot is called a Fowler-Nordheim plot (Good and Muller, 1956). 

The dipole moment of adsorbed atoms can be derived by measuring the change in work function as a result of the presence of the adatoms. In macroscopic measurements, the states of the deposited adatoms are unknown. They may combine into clusters of different sizes and some of them may be absorbed into lattice steps. One can also use the field emission microscope for this purpose. However, similar uncertainties exist. To achieve a well characterized surface and a known number of individual adsorbed atoms on a surface, a combined experiment with field ion microscope observations and field emission Fowler-Nordheim (F-N) plots has been most successful.198,200... 

It should be pointed out here that large decreases in the pre-exponential term of the Fowler-Nordheim equation occur on oxygen adsorption, so that the slope of a log Z/F vs. 1/V plot should be used for determination of X- These decreases were also found by Muller (1) for oxygen and by the writer for hydrogen on tungsten. They may correspond, at least in part, to a decrease in effective emitting area, both micro- and macroscopically. 

Figure 9.7 Left Frumkin-Fowler-Guggenheim (FFG) adsorption isotherms (coverage 0 versus the pressure in units of Kj 1). The curves were calculated using Eq. (9.35) with ft 0,2,4,6. For ft 6 the physically correct adsorption curve is plotted as a continuous curve while the one calculated with Eq. (9.35) is plotted as a dotted curve. Right Adsorption isotherms for krypton adsorbing to the (0001) plane of graphite at two different temperatures. The dotted curves were fitted using Eq. (9.35) with ft = 4.5. Experimental results were taken from Ref. [377],...

FIGURE 2 (a) Emission current and anode voltage characteristic of MOVPE-grown Si-doped GaN hexagonal pyramids on a SiQ2 mask patterned on GaN/HT AIN buffer/6H-SiC and (b) Fowler-Nordheim plot of I-V data [3],... 

FIGURE 14. /- V characteristics showing field emission currents in the range of 0.1 nA to 1 mA, (b) Fowler-Nordheim plot corresponding to the data in (a).47... 

The seminal work in this field was carried out by Kebarle and it is surprising to note the gap of 30 years between the foundation paper hy Bernal and Fowler on solvation in solution and the first examination of the simpler process of hydration in the gas phase. A series of plots showing the concentrations of various hydrate complexes for NafHjO) as a function of the total pressure of water vapor is given in Fig. 2.29. ... 

Extension of the tunnelling problem to three dimensions was first attempted by Itskovich who showed that the band structure of the emitter would affect both the FN plot and TED. Gadzuk and Politzer and Cutler have argued that the spatial extent of the wave-function is important in determining the yield of field emitted electrons, and the latter authors conclude that the Fowler-Nordheim model succeeds for 2>d metals only because the contribution from the 3d band to the total field emitted current is small so that the current reflects the nearly-free-electron character of the 4s-p bands. 

It is well known that nanotubes and nanowires with sharp tips are promising materials for application as cold cathode field emission devices. We have investigated the field emission of different nanowire structures. The first is from SiNWS. SiNWs exhibit well-behaved and robust field emission fitting a Fowler-Nordheim (FN) plot. The turn-on field for SiNWs, which is needed to achieve a current density of 0.01 mA cm , was 15 V p.m [26]. The field emission characteristics may be improved by further optimization, such as oriented growth or reducing the oxide shell, and may be promising for applications. 

Inset Fowler—Nordheim plot. The linearity of these curves indicates that the emission of the oriented SiC nanowires agrees with the properties expected for field emission [68]. 

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