[nialo]

CVD in general is slow and time consuming, but because graphene is just one atom thick growing graphene specifically might not be too bad. Also the process gas/chemistry requirements are relatively very simple.

For reference, I used to see ~4 hour cycle times for growing graphene on copper sheets. I think most of that was in the heat up and cool down, maybe order of 30min actual growth time. These numbers might be off by a factor of 2-5, it's been a few years since that job, and I was a equipment design engineer not a process guy as such.