I was thinking gallium nitride, high electron mobility transistors, and the like (party thusly)I’m sure there’s already a fairly high percentage of germanium in those substrates. Good for putting a hitch in the energy band so that you improve electron current by reducing electron-hole recombination.
What you want to do next is GaAs (gallium arsenide) or InP (indium phosphide).
I’m a lot of fun at parties.