Well, my first
thought is that sand is SiO_2, so you could try to
reduce it to silicon and make transistors.
We'd not be able to make transistors with just sand. There are
essential doping agents. I'm not sure arsenic can be easily extracted
from bamboo...
True, but sand is not _pure_ SiO_2, and there are probably other
rocks/minerals around. You might well be able to extract suitable dopants
from thsoe.
-tony