An element or compound used to enhance a semiconductor is called a/an

When a small, carefully controlled bit of an impurity is introduced into a super-pure substance, the substance becomes a semiconductor.

The element or compound that was added to the pure substance to make it a semiconductor is called a "dopant".

I tried including some more sentences in the answer, to give you other forms of that word, like the ones that rhyme with 'rope', 'roped', and 'roping', but won't allow the use of the word !

15.3 cos 65 degrees trig