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The crystallographic polarity of ZnSe has been identified uniquely by employing X-ray diffraction techniques. The X-ray identification has been correlated with the etch-pit figures formed on the (111)Zn and () Se surfaces. When etched with the K2Cr2O7-H2SO4 solution, the (111) surface is highly polished, while the () surface forms triangular pyramidal shaped pits with positive orientation. Subsequently etched with the NaOH solution, triangular pyramidal shaped pits with negative orientation are formed on the (111) surface, and the positively oriented pits on the () surface formed by the K2Cr2O7-H2SO4 solution develop into negatively oriented pits in triangular pyramidal shape and in addition, triangular pits with flat bottom are formed on the () surface. A similarity in etching behavior has been found between the ZnSe crystals grown from the melt and grown by sublimation techniques.

Single crystals of ZnSexTe1-x having uniform composition were grown on a ZnSe or ZnTe seed over the whole range of molar composition by a vapor-phase sublimation technique. The grown crystal often contains microcrystalline ZnO. Measurable improvements in the purity of the final crystals were achieved by the slightly modified version of the simple vapor-phase sublimation technique, by which single crystals without ZnO inclusions were grown. Optimum conditions for the crystal growth were the temperature difference between the seed and the charge of 7–8°C, the growth rate of 0.1 g/day, and the use of the sintered charge of the complete and homogeneous solid solution of ZnSexTe1-x The grown crystal had welldeveloped (110) surfaces up to 4×3 mm2. The compositional variation was found to be less than ±0.2% throughout the crystal by X-ray lattice-constant measurements.

Optical absorption in undoped ZnTe crystals grown by Piper-Polich method is measured in the photon-energy region from visible wavelegth to 15 µm, at the temperature from 77 to 520 K. In the crystal grown in vacuum, a broadband absorption is observed in the photon-energy region 0.9 to 1.4 eV. It is found that this absorption band consists of a peak and a shoulder at 77 K. This absorption band is attributed to the electronic transitions from the split-off-valence band to the shallower and deeper acceptor levels, most likely due to Zn vacancy. By analyzing the experimental results, the energies of the acceptor levels are estimated to be 0.06 and 0.16 eV above the top of the valence band, and the radii of the acceptor states to be 9.5 and 6.5A, for a shallower and deeper acceptor states, respectively. The spin-orbit splitting at the \varGamma point is determined to be 0.95 eV.

Polycrystalline silicon ribbons were prepared by Roller Quenching Methods. Ribbons obtained were produced at an ultra high speed about 20 m/sec, and the size was 20 µm to 200 µm in thickness and 1 mm to 50 mm in width. Microscopic observations of etched ribbon surface showed that the average grain size were 20 µm to 30 µm. Cross sectional view showed the ribbons in columnar grain structure. Any unwanted impurity was undetectable by an Auger analysis except very thin oxygenated layer on the surface of ribbons. The active carrier concentration of the ribbons was nearly the same with the doped impurity concentration from 1014/cm3 to 1020/cm3, and the Hall mobility parallel to the ribbon axis and perpendicular to the ribbon plane was 1 to 150 cm2· V-1· sec-1 and 700 cm2· V-1· sec-1, respectively. A solar cell using the present ribbon was made by a thermal diffusion method. The satisfactory diode characteristics and the conversion efficiency of about 5% were obtained.

First, it is confirmed that the empirical equation B=B 0 exp (-C/√V) is applicable to the electroluminescent emission from ZnS (Cu, Al) EL phosphors embedded in a dielectric. Then, based on this equation, the frequency dependence of the electroluminescent emission is discussed in detail. The quantities B 0 and C in the above equation are considered with respect to frequency and temperature. According to the experimental results obtained, the emission mechanisms of electroluminescence in this phosphor are considered, principally on the exciting high field, the primary electron source and the recombination process. Finally, it is concluded that primary electrons may be injected through the depletion layer by the tunnel effect and that the recombination process may act on the monomolecular law.

ZnO crystals thin plate-form were grown from molten lead fluoride. The six-fold c-axis is perpendicular to the planes of the crystals. The transmission in the region of the absorption edge is investigated as a function of temperature. At wavelengths beyond one micron, the absorption coefficient α varies with λ2. The effective mass of (0.06 to 0.14)mis derived from the classical expression for free-carrier absorption. An electron affinity of 1.3 eV is deduced from the photoelectric threshold. The temperature dependence of mobility shows the presence of a large impurity scattering at low temperatures.