It has been a while since I studied solid state physics but yes, exactly correct. The fun effects of semiconductors rely on the electronic properties of certai

It has been a while since I studied solid state physics but yes, exactly correct. The fun effects of semiconductors rely on the electronic properties of certain solids (or their electrons, equivalently their absence ie ‘holes’) which take place at a small scale, hence the use of quantum mechanics. Some of these effects can manifest at larger scales, and can be modelled classically too.