<b>Comparative Study of Parallel Vertical Junction Solar Cell Photovoltages</b> This work aims, through a theoretical study, to make a comparison of three different parallel vertical junction solar cells photovoltages Si silicon, InAs indium arsenide and GaAs gallium arsenide . For this we have showed the evolution of these voltages with regard to temperature and the collection of the charge carrier velocity. The photovoltaic cell having the voltage most important is probably more performant.These cells have the same dimensions, are doped with the same doping level and are used under the same conditions of illumination and temperature. The comparative study is made only on their electric photovoltage. This important size for the characterization of cell performance is deduced from the continuity equation resolution. The photovoltages are studied according to the temperature and according to charge carrier’s collection velocity. Photovoltage, vertical junction solar cell, temperature, charge carrier’s collection velocity 1118-1121 Issue-6 Volume-3 Dieme Nf. | Sane M. | Honadia P. Ab. Aziz | Barro F. Id.