Chemical, electrical, and optical measurements were performed on n- and p-type β-silicon carbide crystals grown from pure or doped carbon-saturated silicon melts. Pure, transparent yellow crystals showed no detectable impurities and had carrier concentrations in the range of 1016 cm−3. Extensive twinning was observed. Uncorrected electron mobilities of 700–1000 cm2/V·sec were measured at room temperature. Intense injection electroluminescence, peaking at 2.28 eV and 2.0 eV, was observed in many diodes. Strong photoluminescence was observed in aluminum-doped crystals at 77°K and at room temperature when irradiated with uv light.

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A method of tensile testing is described in which hydrostatic pressure, acting radially against the internal wall of a cylindrical specimen, is utilized to create a uniform tangential tensile stress in the specimen wall. The method is applicable to brittle materials because it eliminates nonaxial stresses due to misalignment and localized stress concentrations which normally arise from gripping or supporting the test specimens. Standard deviations of 1.1 to 2.6% were obtained on plastic and aluminum oxide specimens. The method and apparatus are described, and the results are presented.

The development of an arc-image system for crystal growth, and techniques for obtaining continuous growth of single crystals under controlled atmospheres, are described. Crystals grown include rutile, sapphire, ruby, stabilized zirconia, and ferrites.