Then again, silicon is an atomic crystal, while hair's structure is defined on the cellular level, which makes doping silicon much more practical than doping hair. This is on top of the problem that solids without an atomic lattice of some form tend to have trouble allowing any kind of electron movement at all, regardless of what chemicals you add to it (there are quite a few exceptions, like chlorophyll, but even those tend to be well-defined at the molecular level).

Also, as the author mentions, hair soaked in salt water becomes conductive, not semiconductive - current running through it is simply passed on by the salt water - but this conductivity has nothing to do with the hair and everything to do with the water.