In this paper, we present simulations and the optimization of electrical and optical properties of GaAs Quantum Dots (QD) in a GaAs1-xPx matrix. Our results showed that 25 GaAs/GaAs1-xPx QD layers provide a relative enhancement of 41.34% and 75.40% of the short-circuit current and efficiency, respectively. With the same number of the QD layers, the External Quantum Efficiency (EQE) measurement shows that the absorption range edge of low energy photons has been extended from 875 to 1200 nm (ΔEQE = 25%). The temperature effect has been studied for a different number of QD inserted. The optimal conversion efficiency of 25 QD layers is degraded from 23.50% to 18.70% by increasing the temperature from 273 K to 350 K. Moreover, the electrical features obtained and EQE measurements for GaAs/GaAs1-xPx QDSC have been compared with those obtained for In0.47Ga0.53As/GaAs0.86P0.14 QDSC, In0.167Ga0.53As/GaAs and GaAs reference cell, in order to show the better structure.