Why Zinc oxide is a semiconductor?

Answer 1

A substance is classified as a good/bad/semi conductor based upon the energy gap (band gap) in between the valence bands and conduction bands (which are nothing but the collection of molecular orbital energy levels).

for ZnO the band gap is ~3.4eV (electron volts). this value is more than for a conductor (like most of the metals Cu, Zn, Ag, Au etc) and less than bad conductors (Wood, Paper etc). so ZnO is a semi conductor. these type of materials can be played with to behave as a good or bad conductor.

Answer 2

Zinc oxide, ZnO, has some of the properties of a semiconductor, but finds limited use in this application. Though the band gap of this material can be tuned, that band gap is generally large, and this explains why it has few advantages as a semiconductor. Use it in sunscreen instead.

Answer 3

No it is a conducter.