Papers by Keyword: Polytype

Abstract: The pressure dependences of the second-order elastic constants ij C and the velocity of sound in 3C-SiC and 2H-SiC crystals are calculated in the framework of the Keating model with the additional assumption that the central α and the noncentral β force constants are linear functions of external hydrostatic pressure. Grüneisen parameters for the different acoustic modes of 3C-SiC have been also calculated. The third –order elastic constants ijk C for 3C-SiC are determined from the dependences of ij C on the pressure.

Abstract: We examined the formation of poly-crystals and polytypes under the point of view applying various powder phases. 6H-SiC single crystal was easily grown by using the green (α-SiC) powder, while the poly-crystals were generated when β-SiC powder was utilized. The method of mixed β-SiC and carbon powder and of graphite pipe inserted in β-SiC powder were applied to overcome the generation of poly-crystals, respectively. It was confirmed that the occurrence of poly-crystals in 6H-SiC crystal was successfully suppressed by C-rich environment.