Why does anion vacancy act as a 'hole-killer'?

[khlee1992]

I read an article that anion vacancy act as a 'hole-killer' which prevents p-type doping.

I couldn't understand this sentence first time when I read, so I studied for that.

I finally conclude that this anion vacancy act like positive charge, and this positive charge repel p-type doping.

But I can't assure that is right.

Please help me. I'm really appreciate your help.

 

[Useful nucleus]

Typically the anion vacancy is positively charged with respect to the lattice site (although in some cases it can be neutral also). This means that the creation of this vacancy is associated with the generation of free electrons (to charge-balance the vacancy). The free electrons recombine with the holes and the net outcome is killing the p-type conductivity.