Synthesis and Growth of 6H-SiC and 3C-SiC in an Al–Si–C System at 820 °C: Effect of the Reaction Path on the SiC Polytype

Abstract

Many of the properties of SiC are decided by the polytype. In the present work, the effect of the reaction path on the SiC polytype is studied. Two kinds of SiC particles were prepared at 820 °C in an Al–Si–C system. Results show that 6H-SiC with a hexagonal structure and 3C-SiC with a face-centered cubic structure were obtained separately with a liquid–solid reaction and master alloy method. Further research revealed that 6H-SiC was formed via a one-step reaction with graphite as the precursor, while 3C-SiC was synthesized via a two-step reaction with Al4C3 as the intermediate product and precursor. A different reaction path and precursors result in a different growth process. 6H-SiC was grown under a polynuclear multilayer growth mechanism, while 3C-SiC was grown by a multiregion transition of Al4C3.

Growth of p-type 4H-SiC single crystals by physical vapor transport using p-type SiC powder

“…23 As shown in Fig. 4 and the perfect 3C-SiC crystal was the combination of rhombic dodecahedron and cube simple forms, 24 the morphology of the 3C-SiC particles was more diverse. In Fig.…”

“…This indicated that the synthesized p-type SiC powder was mainly composed of 3C-SiC and a small portion of 6H-SiC. Due to the fact that the perfect 6H-SiC crystal possessed a hexagonal conical prism shape from the side view and a regular hexagon shape from the top view and the perfect 3C-SiC crystal was the combination of rhombic dodecahedron and cube simple forms, 24 the morphology of the 3C-SiC particles was more diverse. In Fig.…”

Shape Evolution and Control of Wurtzite CdSe Nanocrystals through a Facile One-Pot Strategy

“…Polytypes, occurring in different structural modifications, are a special case of polymorphs, which share identical close-packed planes but differ only in the stacking sequence in the third dimension normal to these planes. Polytypes commonly exist in group II–VI, III–V, and IV-IV compound semiconductors, − whose structures generally display cubic zinc-blende (ZB) and hexagonal wurtzite (WZ) forms. As one of the typical II–VI semiconductors, cadmium selenide (CdSe) has attracted extensive interest over the past 20 years, owing to its robust synthetic method − and its ability to tune the optical behavior across the entire visible spectrum.…”