Optically transparent cubic SiC crystals were grown via atmospheric-pressure chemical vapour deposition (APCVD) on graphite substrates from methyltrichlorosilane (MTS) in hydrogen in a coldwall RF induction furnace at temperatures from 1500 to 20008C. The morphology of the crystals was correlated to substrate temperature, H 2 /MTS ratio and hydrogen flow. Low-temperature photoluminescence (PL) spectra exhibited a zero-phonon line (2.3787 eV) attributable to an exciton bound to a neutral nitrogen donor, in addition to TA, LA, TO, and LO phonon replicas. The observed broadening and splitting of the PL spectral lines were associated with the morphological habit and internal strain of individual crystallites.
Above about 16008C preferential h110i growth directions were identified for the majority of the crystals. At intermediate deposition temperatures (1600-17008C) the dominant morphology consisted of yellow prismatic crystals heavily twinned along {111} and {11 " 1}. At temperatures of about 17508C hexagonally shaped {111}-oriented 3C-SiC platelets were formed with alternating {001}/{101} edges. A layer-by-layer growth model was used to rationalise the transition in preferred growth direction from h h111i i to h h101i i with increasing substrate temperature. *