Metal evaporator

Thin-film media can be made by various technologies, eg, sputtered deposited Co—Cr—X films for longitudinal appHcations, laminated media for hard disk apphcation, metal evaporated tape, and multilayers for possible appHcations in magnetooptic recording. 

Fig. 20. Mass-production equipment for metal evaporated tape (103) vacuum - 1 mPa (10 torr).

Fig. 21. Transmission electron micrograph (tern) made from a cross-section of a metal-evaporated tape medium with the typical banana-like shape of...

The direct American process is basically a metallurgical operation. Ziac oxide ores are reduced usiag coal (qv) ia a rotary kiln at temperatures of 1000—1200°C to 2iac metal. At these temperatures the produced 2iac metal evaporates and is oxidi2ed with air to ZnO ia the upper part of the kiln. 

The interpretation proposed for the LnB phases can be extended to alkaline-earth and potassium hexaborides. These dissociate through metal evaporation, yielding a j3-rhombohedral boron residue at the mp for CaB , SrB5 and BaB , and at 750°C for KBft. 

The problems raised by the preparation of some rare-earth borides such as SmB4, YbB4 and TmB2 are comparable to those found for the alkali borides from the point of view of the volatility of the metals. They dissociate through metal evaporation, yielding boron-rich borides as indicated in 6.7.2.4. 

To remove any metallic Au, the reaction mixture is evaporated to dryness and subsequently passed over a commercial terra infusorii column in a minimal volume of solvent. Crystallization may be performed by slow diffusion of a two-layer system. Yields are low (10-60%). The metal evaporation technique (see 8.2.1.2) gives higher yields than the sodium borohydride method. 

A rotary apparatus is used for metal evaporation as shown in Fig. 1. Similar equipment is employed for the preparation of organometallics. For Au clusters, Au metal is evaporated from a resistively heated W boat onto an ethanol film, in which the reactants, e.g., AufPAr IX and/or PAr, are dissolved (see Table 1, method B, 8.2.2.2). 

Palladium clusters deposited on amorphous carbon have been studied by XPS and UPS [28] and both techniques show broadening of the d-band peak as cluster size increases. The d-threshold shifts towards Ep as cluster size increases. In UPS studies the d-emission of the single atom has its peak at 3.0 eV below Ep, whereas the d-threshold is 2eV below Ep. Palladium clusters evaporated onto Si02 have been studied by UPS [38]. At large coverages of the Pd metal evaporated (> 10 atoms/cm ), a high emission intensity at Ep excited with photons of 21.2 eV (He(I)) or 40.8 eV (He(II)) as excitation source, is observed. This feature is characteristic in the spectra from bulk Pd samples. At the lowest metal coverage (3 x 10 atoms/cm ),... 

These examples show that by means of metal nanoclusters SET is accessible at room temperature. However for highly redundant SET devices, particle-size distribution has to be avoided, which is not possible when metal evaporation is used for cluster fabrication in the examples given above. 

FIG. 5. Schematic representation of the ASTER deposition system. Indicated are (I) load lock. (2) plasma reactor for intrinsic layers. (3) plasma reactor for />-type layers. (4) plasma reactor for t -type layers, (5) metal-evaporation chamber (see text). (6) central transport chamber. (7) robot arm. (8) reaction chamber, (9) gate valve, (10) gas supply. (11) bypass. (12) measuring devices, and (13) tur-bomolecular pump. 

Fig. 3.10. Reaction cell. 1 - Atom gun 2 - Thermostate 3 - Metal evaporator 4 - Pt/Pt-Rh thermocouple 5/7 - Collimation holes (diameter 3 mm) 8 -Shutter 9 - ZnO semiconductor sensor 10 - Mobile quartz weight 11 - Platinum contacts terminals 12 - Vitrificated iron bars controlled by a magnet 13 -Quartz guides...

Haick H, Niitsoo O, Ghabboun J, Cahen D (2007) Electrical contacts to organic molecular films by metal evaporation effect of contacting details. J Phys Chem C 111 2318-2329... 

In an alternate process, a variation of the above method, molten lead is atomized in a shaft furnace. An air stream carries the very finely divided metal into the hot zone of the shaft furnace where the metal evaporates and oxidizes producing very finely divided lead monoxide. The product is passed... 

Many published results on electronic transport properties of organic materials, where metal contacts are usually made by evaporation of metals, do not describe the quality of the organic/metal interface, and some exotic observed features may perhaps be ascribed to extrinsic effects such as metal diffusion. The relatively simple contact lamination technique may become an alternative, since it provides a means for establishing electrical contacts without the potential disruption of the organic material associated with metal evaporation. The method consists in bringing the organic layer into mechanical contact with an elastomeric element coated with a thin metal film, which can also be patterned. The contacts are robust and reversible... 

Haick H, Ambrico M, Ghabboun J, Ligonzo T, Cahen D (2004) Contacting organic molecules by metal evaporation. Phys Chem Chem Phys 6(19) 4538 541... 

A static glass or metal vacuum chamber with cooled walls, housing a metal evaporator and a system for distributing the vapor of compounds to be condensed with the metal atoms onto the cold walls (Fig. 2). The system for distributing vapor can be quite crude and yet effective because of the rapid expansion of vapors under the high vacuum in the... 

A rotating, evacuated, cooled flask containing a metal evaporator (Fig. 3). Metal atoms can either be condensed with vapors or condensed... 

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