Spontaneous emission of light in semiconductor LEDs produces light that lack fixed-phase dependence; it is a question of incoherent light. However, it was proved that spontaneous emission depends not only on intrinsic property of material but also on the surrounding environment. Association between Quantum Dots (QD) and Photonic Crystals (CP) can have this role and modify characteristics of spontaneous emission and obtain wished results. In this paper we present another way to produce spontaneous emission with new interesting performances to arrive in produce a single photon source which produce indiscernible unique photons. Such sources are useful in quantum cryptography and quantum computing.