摘要： In this work we study and optimize the single solar cell efficiency of GaNxAs1-x-ySby and Ga1-xInxNyAs1-y deposed on GaAs. The solar cells are simulated, in the aim to find the best concentration of nitrogen and antimony for GaNxAs1-x-ySby, and indium and nitrogen for Ga1-xInxNyAs1-y which gives us a band gap energy around 1 eV with a low strain and a maximum absorption, in fact we do not have only one value but a whole interval for both structures. In the second step we simulate the efficiency of both GaNAsSb and GaInNAs solar cells with the find concentration values in order to see which of the two structures will give a higher efficiency. We noticed that the results were obtained under AM1.5 illumination, 300 K and an ambient pressure. The two structures had a thickness of 300 nm. The N and P layers have a doping level of 1.1015 cm-3 and 1.1016 cm-3 respectively. This study gives us the possibility to produce multi-function solar cells.