In this paper, we theoretically investigate the effect of the doping concentration on the properties of one dimensional semiconductor photonic band structures. Our numerical method is based on the transfer matrix method. The numerical results show that the photonic band gaps in is sensitive to the changes in the doping concentration. In addition, the width of the gap of is less sensitive to the change in the doping concentration. Our structures could be of technical use in optical electronics for semiconductor applications. We have designed the first case is (SiO2/GaAs)N photonic crystal (PC) without defect layers and the second case are (SiO2/n-Ge/GaAs)N and (SiO2/GaAs)ND( SiO2/GaAs)N photonic crystals with defect layers. The numerical results show that the number of photonic band gaps (PBG) in the second case (PC with defect layer) is greater than that in the first case (PC without defect layer).