The density of states in a-Si:H, prepared by mercury-sensitized photo-CVD, was measured by the space-charge-limited current method. The density of Si dangling bonds (N s) was measured by the electron spin resonance method. N s and a minimum of the density-of-state near the Fermi level (N min) indicated the same tendency versus substrate temperature, which showed a good correlation between N s and N min. Both N s and N min showed a minimum value near substrate temperature of 200°C. Photosensitivity reached more than 1×106 for the sample.

Hydrogenated amorphous silicon (a-Si:H) films were prepared by mercury photosensitized decomposition of silane using a low-pressure mercury lamp. The deposition rate showed an activation type for substrate temperature (the activation energy: 0.13 eV), because the deposition rate would be determined by the rate of hydrogen elimination from the hydrogen saturated surface. Moreover, the relationship was found between the Si-H2 bond density in a- Si:H films and the gas phase reactions.

We study black holes in AdS-like spacetimes, with the horizon given by an arbitrary positive curvature Einstein metric. A criterion for classical instability of such black holes is found in the large and small black hole limits. Examples of large unstable black holes have a Böhm metric as the horizon. These, classically unstable, large black holes are locally thermodynamically stable. The gravitational instability has a dual description, for example by using the AdS 7 × S 4 version of the AdS/CFT correspondence. The instability corresponds to a critical temperature of the dual thermal field theory defined on a curved background.

Hydrogenated amorphous silicon (a-Si:H) films were prepared by mercury photosensitized decomposition of silane-hydrogen (or-helium) gas mixtures. In hydrogen dilution, a-Si:H films were deposited from 20-100% of the silane fraction and hydrogenated amorphous-microcrystalline mixed-phase silicon (µc-Si:H) films were deposited for less than 10% of the silane fraction. The Si-H2 bond density and optical gap for a-Si:H films increased upon decreasing the silane fraction. The preferential orientation of the crystallites in µc-Si:H films was greatly changed by the silane fraction. However, the film characteristics did not change upon helium dilution. It was found that the hydrogen radical plays a significant role in the film-deposition process. Large-grain-size µc-Si:H films have been obtained, as compared with the grain size for films made by the conventional glow-discharge technique.

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