What is the correct way to build an armchair-zigzag heterostructure device?

[qweasel]

From first look, dragging a zigzag into an armchair and using move->fuse and quick optimizer seems to work. However, when I do hydrogen passivation, several artefacts become apparent (see attach):

• Only part of the edges got passivated.
• Several "normal" sp2 hybridized carbons were unnecessarily passivated.

What is the correct way to make such a device?

[Anders Blom]

I supposed you intended to build a ribbon, but it's still a periodic structure in the B direction, so there isn't really an edge, and thus it doesn't need/cannot be passivated.

For sp2 vs. sp3, I suggest using the Coordinate Tools>Custom passivator and choose sp2, instead of the passivator button, since it gives more options.

[qweasel]

Good point, thanks!
Now I'm experiencing a related "anomaly": hydrogen from a passivated ribbon edge gets cloned into the electrode (attached).
Why does it happen twice? Is it correct to simply delete it from the electrode regions?

[Anders Blom]

Can you attach the structure without hydrogens (or, ok, with, I can always delete them). Then we can check

[qweasel]

Attached.

[Anders Blom]

The correct procedure is to first create the device (Device from bulk) and then passivate, not the other way around, in which case the edges in Z are passivated which they should not be since the device is (semi)infinitely periodic in Z.