Building 6H-SiC, does this look right?

Richie9384 · Aug 1, 2015

I'm having some difficulty understanding how to assemble a particular polytype of SiC and I think I may have made a mistake...my solid state knowledge is limited.

Basically I start with a hexagonal unit cell for SiC (Moisssanite; four atoms), I attached an image of this unit...I then extended it to build what I think is the unit cell of 6H-SiC (12 atoms)...then I extended the unit cell 5X5X1 (ABC) 6H-SiC so I can run tests on the (0001) and (000-1) surfaces.

Ball-and-stick render of a small SiC molecular fragment viewed along the x axis, with a Y and Z axis key at top right and labels A, B and C at left.

Moissanite Hexagonal SiC

Ball-and-stick side view of a zigzag chain of silicon and carbon atoms with a box outline, labelled 6H-SiC Hexagonal, with axes Y, Z and A, B marked.

6H-SiC Unit Cell

Perspective ball-and-stick model of a slab of silicon carbide crystal lattice, tan silicon atoms and grey carbon atoms, with a thin-line bounding cell and x, y, z axis triad in the corner.

Rotated View of the 5X5X1 Structure

Side view in the yz-plane of a layered silicon carbide crystal supercell, showing grey and gold ball-and-stick atoms in stacked hexagonal rings with axes labelled Z, Y and X, and cell corners labelled A, B and C.

Another view in the yz-plane

Dr Transport · Aug 2, 2015

isn't 6H-SiC just hexagonal closed packed? It has been a long time since I looked at the polytypes of SiC

Richie9384 · Aug 3, 2015

Dr Transport said:

isn't 6H-SiC just hexagonal closed packed? It has been a long time since I looked at the polytypes of SiC

Yes, I'm just trying to verify if I'm assembling this correctly. I'm having a hard time understanding some of the solid state jargon and concepts about crystals and lattices.

Diagram of the zig-zag chain stacking of hexagonal SiC for 2H, 4H and 6H polytypes, showing silicon and carbon atoms in layers labelled A, B and C with h and c site notation.

The 6H-SiC unit cell is shown in this diagram.

Building 6H-SiC, does this look right?

Discussion

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