Which plane of GaN gives an image of dots placed hexagonally

[LotsEp]

An electron microscope image of GaN seen in projection shows white dots which correspond to columns of gallium atoms observed in projection. The dots show a hexagonal pattern but there is not a dot in the centre of each hexagonal. No nitrogen atoms are seen in the image. Which plane of this wurtzite crystal is being viewed along>

 

[ZapperZ]

An electron microscope image of GaN seen in projection shows white dots which correspond to columns of gallium atoms observed in projection. The dots show a hexagonal pattern but there is not a dot in the centre of each hexagonal. No nitrogen atoms are seen in the image. Which plane of this wurtzite crystal is being viewed along>

This is awfully vague. First of all, can't you cite your source, or show the actual image?

Secondly, what kind of "an electron microscope" is this? SEM? TEM? PEEM? etc... Please note that it would extremely helpful if you present a full, complete, and concise information when you are seeing help such as this. And always make it a habit to provide full citation to the source!

Zz.

 

[LotsEp]

I have been given a handout with the question and this photo. The type of electron microscope is not specified either. This is as much information as I have. How much can we deduce from this image?

 

[ZapperZ]

I have been given a handout with the question and this photo. The type of electron microscope is not specified either. This is as much information as I have. How much can we deduce from this image?

You have a plane of single-crystal hexagonal lattice. If you have a fiducial length on the screen (i.e. a scale), then you can estimate the lattice constant.

Zz.

 

[LotsEp]

Along which direction in a wurtzite crystal is that? Sorry I am very new to the field...

 

[Hongtu]

Along which direction in a wurtzite crystal is that? Sorry I am very new to the field...

If it is Wurtzite GaN, the hexagonal arrangement of atoms is a clear evidence of c-plane. As in which c-plane (Ga-face or N-face) is beyond my knowledge. So you are viewing along the c-direction. Correct me if I'm wrong.