▎ 摘　　要

The electronic, magnetic, and optical properties of graphene (gr) containing selenium impurities of 2, 3, 5.5, and 12.5% were calculated by DFT. By increasing the percentage of Se impurity, the energy gap decreases from about 0.3 eV for the gr+Se(2%), to about 0.1 eV for gr+Se(3%) monolayer. Continuing this trend leads to metallic property for gr+Se(5.5%) and gr+Se(12.5%) cases. By decreasing the percentage of Se impurity as a non-thermal control parameter, the magnetization started from zero and gradually increased so that the phase transition occurred. By calculating optical properties, using TDDFT, we found that in the absorption spectrums, a visible peak appeared for the cases of Se(3%) and Se(5.5%), and in the gr+Se(12.5%) layer, there exist an infrared shoulder. Also, except for gr+Se(3%), other cases have one peak in the UVA range. Finally, in the gr+Se(2%) case, for all optical variables, the peaks are sharper and stronger, therefore this case could behave as a quantum dot.