基于石墨烯场效应晶体管的光电混频器研究

Research of Optoelectronic Mixer Based on Graphene FET

研究了基于石墨烯场效应晶体管(GFET)的光电混频器(Optoelectronic Mixer,OEM)。器件采用叉指电极结构,增大了器件的光吸收效率,并避免了顶栅结构栅金属对光的反射作用。采用基于7.62 cm硅基GFET的圆片工艺,实现了栅长为1μm共8指的器件制备。测试结果表明,器件的工作频率达到20 GHz。在20 GHz工作频率下,器件光探测响应度达到2.8 mA/W,光载20 GHz射频变换到1 GHz中频的混频效率为-15.87 dB。

The optoelectronic mixer based on graphene field effect transistor was researched. To improve the optical absorption efficiency by the graphene and avoid the reflection of the incident light by the top gate electrode,the interdigital electrodes were adopted. The device was fabricated on silicon wafer by the 7.62 cm silicon GFET process. The fabricated device had 8 interdigital electrodes with gate length of 1 μm. An experimental measurement was performed,which showed that the operating frequency of the OEM could be over 20 GHz for both photodetection and optoelectronic mixing.In particular,the photoresponsivity was 2.8 mA/W for 20 GHz photodetection. Futhermore,a 20 GHz optical microwave signal was used and successfully down-converted to a 1 GHz IF signal,and the mixing efficiency was measured to be-15.87 dB.