In solid state physics the "holes" usually regarded as an effective positive charge carriers. In order to have neutral charge some object needs to have an equal amount of protons and electrons. If some material such as an intrinsic semiconductor has equal amount of protons and electrons + some amount of free holes (which are effective charge carriers) does it mean this one material suppose to be positively charged? If not, why? And which effect carrier generation/recombination does have on total charge of particular object? Also question: which laws govern carriers generation/recombination in metals? Do they suppose to change in metal with change in temperature? And if not, why?