Films annealing

FIG. 34. NMR spectra taken from (I) a highly nitrogenated a-C(N) H film as deposited (2) a highly nitrogenated a-C(N) H film annealed (3) a low nitrogen content a-C(N) H film as deposited (4) an a-C H film as deposited. (Reproduced from [86].)... 

Fig. 16. Butene-1 hydrogenation over Cu-Ni alloy films, annealed in hydrogen at 530°C (117).

The Schottky barriers were excellent diodes for films annealed at 600 °C, with turn on voltages of 0.6-0.8V and minimal reverse bias leakage.48 However, many of the contacts on the as-deposited films gave large reverse bias currents and nearly ohmic responses. This behavior is indicative of degeneracy of the semiconductor because of a high carrier density resulting from native defects. The improvement in the diode behavior of the annealed films is attributed to enhanced crystallinity and reduction of defects. 

The electrodeposited precursor films, annealed in air at 870 °C in the presence of a TBSBCCO pellet, produce a biaxial textured Tl-1223 phase, as confirmed by an XRD pole-figure measurement. The omega and phi scans indicate full-width at half-maximum (FWHM) values of only 0.92° and 0.6°, respectively, which indicates a very high-quality film. The superconductive transition temperature of the Tl-1223 film, determined resistively, was about 110 K. Figure 7.11... 

More recently, it was shown by List et al. [293-296] and later by Moses et al. [246] that the green emission of the PFs is due to fluoren-9-one defects in the polymer chain. This was confirmed by comparison of PL films annealed in an inert atmosphere and in air a progressive additional band in the green region was observed on annealing in air (Figure 2.12) [246],... 

Fujiki and coworkers [290] synthesized asymmetrically substituted PFs, bearing a bulky Frechet-type dendron and a less bulky 3,6-dioxaoctyl group in position 9. The polymers 215-217 showed a pure blue PL emission with rather low green emission band (at 520 nm) for the films annealed at 200°C for 3 h (in vacuum) (Chart 2.51). 

Figure 4.12 Normalized DSC thermograms of PET films annealed at 180 °C for the indicated times [47]. From Lin, S. and Koenig, J., J. Polym. Sci., Polym. Symp. Ed., 71, 121-135 (1984), Copyright John Wiley Sons, Inc., 1984. Reprinted by permission of John Wiley Sons, Inc...

PNT-N film annealed In Nitrogen for 1/2 h. PNT-F film annealed fai Nitrogen for lA b. 

Kokai J, Rakhshani AE (2004) Photocurrent spectroscopy of solution-grown CdS films annealed in CdCE vapour. J Phys D 37 1970-1975... 

For a 6 pm thickness of the nanotube array film annealed at 600 °C the quantum efficiency was calculated to be 81% and 80%, for wavelengths of 337 nm (3.1 mW cm ) and 365 nm (89 mW cm ), respectively. The high quantum efficiency clearly indicates that the incident light is effectively utilized by the nanotube arrays for charge carrier generation. 

CoSe was deposited using a similar composition to that for CoS, except that selenosulphate was used in place of thioacetamide, NaOH and hydrazine were also added to the solution, and the deposition was carried out close to 100°C [37]. In contrast to CoS, no XRD pattern was observed for the as-deposited films annealing at 280°C crystallized the films to give a defined pattern corresponding to CoSe. A direct bandgap of 0.45 eV was estimated from the optical spectrum. The films were p-type and the resistivity 10 O-cm. 

MnS was deposited from a room-temperature solution of Mn(II) acetate complexed with triethanolamine and buffered with NH4CI [73]. Thioacetamide was used as a sulphur source, and hydrazine was also used (it was not specified whether the reaction proceeded in its absence). No XRD pattern was seen in the as-deposited (grey-pink) film annealing at 500°C in an inert atmosphere gave a pattern corresponding to MnS. A bandgap (indirect) of 3.25 was measured from the optical spectrum. The film was p-type with a resistivity of ca. 10 O-cm. 

In a similar study, (Cd,Pb)S was deposited on Ti at ca. 75°C [17]. The ratio of Cd to Pb in the films was found (by atomic absorption spectroscopy) to be very similar to that in the solution, a consequence of the similar values for the solubility product of the two sulphides. Since the main purpose for investigating these films was to study their photoelectrochemical properties (see Chap. 9 for details), little no characterization, other than compositional and photoelectrochemical, was made. Photoelectrochemical spectroscopy (of films annealed at 460°C in air for 4 hr) showed a decrease in bandgap with increasing Pb content down to 1.6-1.7 eV for Cdo.siPbo.igS, although very nonlinearly—a strong drop in bandgap, of 0.5-0.6 eV, occurred between 0.1 and 0.18 mole fraction Pb. 

Fig. 8.3 Resistivity vs. Cu In ratio for Cu—In—Se films (annealed at 520°C). (Adapted from Ref. 43 with permission from Elsevier Science.)... 

In contrast to CdSe, most studies on CdS involved either nonannealed films or films annealed at relatively low temperatnres. Relative efficiencies (i.e., taking into acconnt that the efficiency of the higher-bandgap CdS will be lower than that of CdSe dne to its lower light absorption) are therefore low. Additionally, most PEC stndies on CD CdS involve doped films, where ions of the dopant were added to the deposition solntion. 

In Ref 52, no XRD pattern was observed in the as-deposited films. Annealing at 450°C resulted in a bandgap of 3.7 eV (and conversion of some of the ZnS to ZnO). This value suggests that hexagonal ZnS is formed (at least, after annealing). 

Poly crystalline silicon (poly-Si) has been formed by the plasma-enhanced decomposition of dichlorosilane in argon at temperatures above 625 °C, a frequency of 450 kHz, and a total pressure of 27 Pa. Doped films have been deposited by the addition of phosphine to the deposition atmospheres (213). Approximately 1 atom % of chlorine was found in the as-deposited films. Annealing in nitrogen at temperatures above 750 °C caused chlorine to difluse from the film surface, grain growth to occur, and the film resistivity to drop. Such heat treatments were necessary to achieve integrated-circuit-quality films. 

To achieve in-plane alignment in a lamellar block copolymer thin film, the lamellae have to be oriented perpendicular to the plane of the film in the first place. As we have shown earlier, in the block copolymer system S47H10M4382 perpendicular alignment of the lamellae is achieved spontaneously at zero electric field [9, 17]. In short, a thin brush layer of the block copolymer is adsorbed onto the (polar) substrate via the PHEMA middle block, resulting in a stripe pattern of the two majority components PS and PMMA. In thicker films, this brush layer seems to serve as a template for perpendicular lamellae [21, 22], This can be seen in Fig. 2a, which shows SFM images of a thin S47H10M4382 film annealed for... 

Fig. 4 (a) SFM phase image (3x1.5 im) of the surface structures in SB47 films annealed in vacuum at 120°C. The white contour lines are taken from the height image (not shown) and mark the borders between the flat regions, as well as the transition region between the indicated terraces, (b) Spacings of cylindrical microdomains as a function of the local film thickness... 

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