Take the 2-minute tour ×  I have read that holes in
semiconductor are nothing but vacancies created by electrons.
But how can this vacancy i.e. hole has a mass?  share|improve
this question See physics.stackexchange.com/a/10858/3811 for
more details about "what is a hole" than you usually find :-) – 
Steve B Jul 10 '12 at 22:57  4 Answers 4  A quick answer:
Imagine an array of billiard balls with one missing in the
middle of the array; there is a "hole" where the billiard ball
is missing. For this hole to "move", a billiard ball must move
into that position, leaving a hole at the ball's previous
position. Since, in fact, the hole movement is entirely
equivalent to the billiard ball movement, we can speak of the
mass of the hole even though it is the billiard ball's mass that
is physical.  Now, in the case of electrons moving through the
unfilled valence band, the effective mass is greater than the
mass of a mobile electron so hole mass is typically greater than
mobile electron mass.  share|improve this answe