Target preparation vacuum evaporation

Figure 6. Plan of the target preparation facilities consisting of UHV preparation chamber (a), (reactive) ion etching chamber (b), ion etching gun (c), laser (d), photon detector (e), transfer arms (f), Auger system for surface analysis (g), sample manipulator and annealing facility (h), load lock and optical microscope for viewing sample (i), evaporator (j), transmission diffractometer (k), and vacuum tank for main spectrometer (1).

Boron films have been prepared by means of chemical vapor deposition (6-8), vacuum evaporation using electron bombardment of boron (9-11), and sputtering of a boron target. The several methods mentioned are summarized in Table 1. 

Techniques such as vacuum evaporation method, melting process in a glass matrix, and so on [88], basically fundamental fabrication techniques for inorganic NPs and semiconductor quantum dots, would not be expected to be applied to organic and polymer compounds and materials because of their thermal instability [89, 90]. In contrast, the so-called reprecipitation method [1-4] is a useful and convenient procedure to prepare organic and polymer NCs. This method has been further improved as the supercritical reprecipitation method [1-3,28,29], reprecipitation-microwave irradiation method [1-3, 30-34], and inverse-reprecipitation method [1-3, 27, 42, 43], being closely related to the physicochemical properties of the target compound and materials. 

Gas evaporation using Ar for the preparation of various sort of metal fine powders was first reported by Kimoto et al. in 1963 (5). The production chamber of this method is basically the same as that of a vacuum sublimation chamber. A target material is heated in this chamber with several torr inert gas atmosphere. The nanometer-sized particles are easily formed in the chamber space. However, by this method, it is difficult to get genuine nanoparticles whose sizes are several nanometers. This is because of the radiation heating in a production chamber, resulting particle coalescence on the chamber wall or particle collector, as well as the direct particle contact in the deposited particle layer (powders). Therefore the size becomes several tens to hundreds of nanometers. Several ultrafme metallic powders are now commercially available, including Cu, Ag, Al, Ni, Co, Fe, and Au, with a size of several tens of nanometers. 

The PTCDI films with thickness of 100 nm were prepared by laser evaporation in vacuum of 10 Pa. The LGN-703 infrared C02-laser with output power of 40 W was used for evaporation of powdered PTCDI target. The products of evaporation were deposited onto the glass-ceramic and mica substrates at 20°C (cold) and 150°C (hot). The glass-ceramic substrates contain a preliminary formed interdigital system of nickel electrodes. 

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