The luminescence induced by α particles in GaAs/Al0.35 Ga0.65As multiple quantum well (MQW) semiconductor was detected and investigated. The luminescence was observed at liquid nitrogen and at room temperatures as light flashes induced by individual α -particles. The MQW samples studied, in addition, were investigated using a standard photoluminescence method to show that α -particle created flashes are associated with the radiative decay of 2D excitons in quantum wells. Since the number of detected light quanta in a flash is critical, a discussion of the collection efficiency of photons created by a single α -particle is presented