The purity of gallium required for the production of semiconductors is a lot higher than that. According to wikipedia "Because of this application, extremely high-purity (99.9999+%) gallium is commercially available".

I am not sure how much this costs, or whether a lower grade can be used and purified somehow (dount it).

At any rate, I doubt the cost of the gallium is an issue, compared to all of the other cost savings and benefits with the POET process.

http://en.wikipedia.org/wiki/Gallium

Cheers,

Quan