Low-energy electron beam

D) LOW-ENERGY ELECTRON BEAM (RETARDING-POTENTIAL) METHODS... 

A low-energy electron beam can also be obtained using a field emission tip and used in the field emission retarding-potential method. This combination provides an absolute measure of the sample work fiinction and the resolution is excellent [52]. 

LEED beam is reduced to less than the sample grain size, individual grains in a polycrystal can be investigated. It is difficult to make low-energy electron beams this small, but in some materials large grain sizes can be achieved in polyctystals. 

Commercial versions of PR are available. Other contactless methods of electro-modulation are Electron-Beam Electro-reflectance (EBER) and Contacdess Electroreflectance (CER). In EBER the pump beam of Figure 2 is replaced by a modulated low-energy electron beam (- 200 eV) chopped at about 1 kHz. However, the sample and electron gun must be placed in an ultrahigh vacuum chamber. Contactless electroreflectance uses a capacitor-like arrangement. 

Low dust (tail-end) plant, 10 101 Loweite, 5 785t Low emittance coatings, 23 16 Low energy dyes, 9 195, 416 Low energy electron beam irradiation, silicone network preparation via, 22 567... 

Secondary ion mass spectra were measured using a Perkin-Elmer+PHI 3500 instrument. Experiments were carried out with 4 kV Ar ions at beam currents of 3 and 300 nanoamps. Spectra were measured to at least 500 daltons (d). Samples were prepared in the manner used for the XPS studies. For measurements on the pure complexes, sample charging occurred, as evidenced by the inability to record secondary ion mass spectra. To reduce charging, a low energy electron beam (50-400 eV) was rastered across the sample during SIMS analysis. Positive and negative ion SIMS spectra were recorded however, only positive ion spectra are of interest for this discussion. In the spectra only unipositive ions were detected, so that the mass numbers detected correspond to combinations of the various isotopes of the elements in the ion. Thus an ion at m/z 17 d is assigned to... 

The operating characteristics of the four most widely used low-energy electron beam processors are shown in Table 3.2. 

The theoretical framework for hydrogen interactions with acceptors presented in Section D1 explains the necessity of an activation procedure when Mg-doped GaN is grown by MOCVD. During cooldown acceptor-hydrogen complexes are formed. In order to activate the Mg, the complexes have to be dissociated and hydrogen neutralised or removed from the p-type layer. This can be accomplished by treatments such as low-energy electron-beam irradiation (LEEBI) [13] or thermal annealing [10],... 

Sensitivity and depth resolution. The use of a low energy electron beam to excite molecular vibrations physically guarantees a very high surface specificity (101. 

Okabe S, Tabata T, Ito R. (1961) Nonobstructive low energy electron beam monitor. Rev Sci Instrum 32 1347-1348. 

Bermudez VM. (1999) Low-energy electron beam effects on poly(methyl methacrylate) resist films. / Vac Sci Technol S 17 2512-2518. 

Olsen C, Rowntree PA. (1998) Bond-selective dissociation of alkanethiol based self-assembled monolayers adsorbed on gold substrates, using low-energy electron beams. / Chem Phys 108 3750-3764. 

Radiation vulcanization of natural rubber latex by low energy electron beams — Use of... 

Laser ablation microprobe mass spectroscopy Low energy electron beam projection lithography Line edge roughness Maleic anhydride Methacrylic acid... 

In a recent study of CO adsorbed on an ion bombardment cleaned Ni(lOO) crystal, Armstrong 210) showed that an ordering of the adsorbed CO could be easily induced by a low energy electron beam and that... 

Penetration of an incident low energy electron beam (say 100 eV) is only a few layers, unlike X rays with radiation so penetrating that the surface region has negligible effect on the diffraction pattern. A primary X-ray beam is hardly attenuated after passage through thousands of crystal planes. In LEED, the interaction with the uppermost layers is intense, and a diffraction pattern corresponds to interference of waves scattered by superficial planes only. Reciprocal space is diperiodic for slow electron diffraction from a regular surface, and is modulated in... 

There are many ways to measure the work function or work function change which can be generally classified as electron emission methods (thermionic emission, field emission and photoelectron emission), low-energy electron beam (retarding-potential) methods and capacitance methods [M, 51 and 52]. Absolute work function values can be measured using emission methods while the other techniques measure only work-function changes. 

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