Why are holes found only in semiconductors?
Here is what i have understood by my own logic :
A hole is the absence of an electron in the valence band. It behaves like a positive charge.
In a metal , there is practically no difference between a valence electron and free electron. ie. Every valance electron is also free to participate in conduction
as the valence and conduction bands overlap.
So , Holes are not formed.
Is this correct?
But what about insulators? For example , air.
Suppose we apply a very large voltage , the valence electrons in the air molecules will gain sufficient energy to become free electrons and air will become ionized.
When this happens , will holes be formed at the places where the valence electrons previously existed?
Here is what i have understood by my own logic :
A hole is the absence of an electron in the valence band. It behaves like a positive charge.
In a metal , there is practically no difference between a valence electron and free electron. ie. Every valance electron is also free to participate in conduction
as the valence and conduction bands overlap.
So , Holes are not formed.
Is this correct?
But what about insulators? For example , air.
Suppose we apply a very large voltage , the valence electrons in the air molecules will gain sufficient energy to become free electrons and air will become ionized.
When this happens , will holes be formed at the places where the valence electrons previously existed?