Which has bigger thermal noise? Resisters or semiconductors?

Answer 1

Resisters

The soul purpose of a resister is to change electrical energy into thermal energy.

Semiconductors store energy, channel energy, and provide some resistance, but the don't dedicate themselves to just dumping heat; that's what resisters do.

I remember in a basic electronics class a group of kids put a 4 ohm coil resister in a 110 volt circuit at 20 amps. If you put a sheet of paper on top of the coil it would ignite in only a few seconds.