基于在石墨烯片两端外加正负电压构成PN结的方法, 通过调节门电压和偏压，研究了光电导和光吸收与外加电压、无序展宽以及温度之间的关系。研究结果表明，石墨烯光电导在太赫兹区出现了负值，光的透射率增大。在太赫兹区，光电导单调依赖于外偏压和无序展宽，而对温度表现出复杂的依赖关系。在外电压一定的条件下，通过选择合适的温度，可增大光的透射率。该研究结论为石墨烯在太赫兹区的应用提供了理论参考。

Based on the method to constitute a PN junction with the addition of external positive and negative voltages at both ends of graphene sheets, the relationships among the optical conductivity and optical absorption with the external voltage, disorder broadening width, and temperature are studied by adjusting the gate and bias voltages. The study results show that the optical conductivity of graphene has negative value in the terahertz region and the light transmissivity increases. In the terahertz region, the optical conductivity depends on the external bias voltage and the disorder broadening width monotonously, but on the temperature complicatedly. Under a given applied voltage, the optical transmissivity can be enhanced if an appropriate temperature is chosen. The study results provide theoretical references for the applications of graphene in the terahertz region.