well, I guess on second look (with more sleep) it makes a little more sense.
My confusion was that, at first glance, it looked like the red, green, and blue sections were supposed to represent the colors emitted, and it looked like the h+ was ionized hydrogen. I just looked at it again and it looks like what they're saying is electrons and holes.
I don't think the colors are supposed to represent the RGB colors (probably a poor choice for their diagram)
Once the gate is activated, an electron crosses the boundry and encounters a hole crossing in the opposite direction, The energetic release in that medium emits light.
As for the chemical stuff to the side, I assume those are the chemical structures of the stuff in the middle, though I know jack about chemistry (my least favorite subject - which is odd, because I married a biochemist)
