Shashiketan,
You have come to the right place.
That above is only the drift current density. There is also the diffusion current density which is -q*Dp*del(p)+q*Dn*del
, where Dn and Dp are the electron and hole diffusion constants respectively, and del
,del(p) are the gradients of the n and p concentrations respectively.
Are you answering your own question?
In the English language, the beginning word of each sentence is capitalized. It makes it a lot easier to read.
At the quantum level, holes have the same status of as electrons, including an effective mass. Holes are only found in semiconductor material. You can read how this is done by doping the intrinsic semiconductor material.
Holes are positive charge carriers. Negative charge carriers like electrons moving in one direction are equivalent to holes moving in the opposite direction. So to answer your question, holes and electrons become current when they move because they are moving charge carriers.