Here we present a graphene photodetector of which the graphene and structural system infrared absorptions are enhanced by interface phonon polariton (IPhP) coupling. IPhPs are supported at the SiC/AlN interface of device structure and used to excite interband transitions of the intrinsic graphene under gated-field tuning. The simulation results show that at normal incidence the absorbance of graphene or system reaches up to 43% or closes to unity in a mid-infrared frequency range. In addition, we found the peak-absorption frequency is mainly decided by the AlN thickness, and it has a red-shift as the thickness decreases. This structure has great application potential in graphene infrared detection technology.

雪崩光电二极管由于具有高增益特性而广泛应用于激光测距机中, 但由于在电流倍增过程中引入的高附加噪声, 使激光测距机进一步提高信噪比遇到了瓶颈。 石墨烯具有高电子迁移率、 零带隙结构、 独特光吸收系数等特性使其广泛应用于激光器、 光调制器、 透明电极以及超快光电探测器。 该研究提出了一种高信噪比的谐振腔型石墨烯光电探测器的设计方法。 以波长为106 μm的激光为例, 采用光学传输矩阵法和散射矩阵法, 研究了光波在谐振腔传输和吸收层吸收的机理, 建立了谐振腔型光电探测器的光吸收模型, 通过优化, 器件最终量子效率达到912%, 响应度达到0778 A·W-1, 半高全宽达到6 nm; 分析石墨烯在谐振腔中的位置对器件吸收率的影响, 发现在满足谐振条件下, 器件吸收率随石墨烯位置呈现周期性变化, 腔长的改变不改变吸收率峰值, 而是改变了吸收率峰值对应的石墨烯在谐振腔中的位置, 当腔长是入射光半波长的n倍时, 随着石墨烯位置变化, 将出现2n个吸收率峰值, 且关于谐振腔中心点对称分布; 选择石墨烯距顶层反射镜0402 8 μm时, 器件吸收率达到94%, 相比单层石墨烯, 吸收率提高了16 dB; 通过对比求解谐振腔型石墨烯光电探测器和雪崩光电二极管信噪比方程, 得出谐振腔型石墨烯光电探测器信噪比可达到903, 较雪崩光电二极管提高了10 dB; 理论分析表明, 谐振腔型石墨烯光电探测器具有高吸收率、 高量子效率和高信噪比, 研究成果将对激光测距机接收系统中光电探测器的更新设计和应用提供理论参考。