Candela class InGaAlP surface-emission green light-emitting diodes (LEDs) have been successfully fabricated. The growth of InGaAlP on an intentionally misoriented substrate improved emission properties, as confirmed by a quantitative estimation of the diffusion length in the active material. A Bragg reflector using InGaAlP was realized for the first time. A new device structure, including this Bragg reflector, drastically improved the light extraction efficiency. An external quantum efficiency of 0.7% at 573 nm green light was obtained, corresponding to a luminous intensity of 2 cd.

Hydrogenated amorphous silicon (a-Si:H) n-i-p diodes in which the intrinsic (i-type) layer surfaces were exposed to an H2 plasma before depositing the p-type layer (H2 plasma treatment of the i/p interface) were prepared. The effects of this H2 plasma treatment of the i/p interface were observed by dark I-V, photo-I-V under 450 nm illumination, and quasistatic C-V measurements. It has been found that the defect density at the i/p interface is reduced by this treatment. It has also been determined that the performance of a-Si:H diodes is improved by this treatment of the interface.

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The divergence and intensity distribution of X‐rays transported through a conical‐type X‐ray guide tube (XGT) were measured. Diverging X‐rays from a point source were condensed by use of the conical‐type XGT. The parallelism of X‐rays through the XGT was better than that encountered for a cylindrical‐type XGT proposed previously [Nakazawa (1983). J. Appl. Cryst.16, 239–241]. The intensity of the X‐ray beam around the central axis of the conical‐type XGT was exceedingly high in comparison with that measured without the tube and almost uniform over a cross‐sectional area 60 μm in diameter. The high intensity provides the possibility of performing diffraction experiments with crystals as small as 20 μm in diameter with a conventional X‐ray diffraction system.

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.