Indium gallium arsenide and gallium arsenide are compound semiconductors that are far too expensive for use in mass market panels. They are used as cells or components of multi-junction cells for satellites and a few other high value applications. Commercial silicon cells are doped with phosphorus and boron or gallium.

On further reading I find that you are correct about RoHS exemptions for lead in solar modules:

https://www.pv-magazine.com/2019/12/07/the-weekend-read-taki...

I appreciate the correction.