Iodine intercalation in Bi2Sr2CaCu2Oy crystals enables one to modify the critical temperature, T(c), of the superconducting phase, and to obtain a semiconductor phase. This doping drastically changes the size of the unit cell. A photoemission spectroscopy study enables us to see that the decrease of the critical temperature is not related only to the change in the c-axis lattice parameter, but also to an over-doping of copper planes (hole doping).