Do holes have physical existence? We know that holes are created due to electrons hopping from one covalent bond to another. But does a hole have a physical existence or it's just a fictitious positive charge, an illusion created by electron movement?
 A: That is true indeed. A hole has no physical existence. It is just the absence of an electron that creates the illusion of a positive charge at that point.
You can find it in Boylested Electronic Devices and Circuit Theory that it's a theoretical thing.
A: Ok, the previous answer by Alchemist is totally reasonable, but I think we could add a bit of "what is real?" into this discussion without getting metaphysical. A hole is a perfectly well-defined mathematical concept, in the same way that an electron is a perfectly well-defined mathematical concept. The mathematical concept of an electron in the theory of solids bears very little resemblance to "real" electrons - which have finite size and additional interactions. I would say that "in the theory of materials, holes are just as real as electrons" and  then you have to decide how real electrons are before deciding that holes are not.
(you ever seen an electron? Yeah ok, they seem to exist in bubble chambers and we need them for QFT, but is that the same as an observation?)
A: Presumably you are referring to semiconductors. A hole physically exists in that it is the absence of an electron. Just like a hole in a piece of paper physically exists. However, if you are asking whether the hole is a particle, then no, it does not physically exist.
In a semiconductor, we deal with electron hole pair (EHP) generation. When this happens, an electron becomes free from the atom it was part of and can move through the crystal lattice. As an electron has been removed, the remaining atom is positively charged and as a mathematical convenience, we just call it a 'hole'. When it comes to concepts like hole mobility, what we are really looking at is the mobility of electrons inside the valence band. Similarly, scattering and other phenomena caused by 'holes' are in fact merely electron interactions in the valence band.
