应用于太赫兹探测器的宽带减反结构设计  

Broadband Anti-Reflection Structure for Terahertz Detectors

作　　者：孙淑菲 靳琳 孙建东[2] 秦华[2] SUN Shufei;JIN Lin;SUN Jiandong;QIN Hua(School of Physical Science and Technology,ShanghaiTech University,Shanghai 201200,CHN;Key Laboratory of Nanodevices and Applications,Suzhou Institute of Nano-tech and Nano-bionics(SINANO),Chinese Academy of Science,Suzhou 215123,CHN)

机构地区：[1]上海科技大学物质科学与技术学院,上海201200 [2]中国科学院苏州纳米技术与纳米仿生研究所中国科学院纳米器件与应用重点实验室,江苏苏州215123

出　　处：《半导体光电》2024年第5期707-712,共6页Semiconductor Optoelectronics

摘　　要：在太赫兹波段,高阻硅和蓝宝石具有低吸收率、高电阻率和低光谱色散等优良特性,常被用作器件的衬底材料。然而,它们的折射率与空气存在较大差异,导致从空气入射的太赫兹波在界面发生大量反射,从而降低了波的透过率;同时,还可能会引发法布里-珀罗谐振腔效应,进而限制太赫兹探测器的工作带宽和灵敏度。为降低界面反射,文章提出一种太赫兹波段的三层减反射结构,借助Matlab中传输矩阵法和电磁场仿真中有限元法进行仿真,筛选出Mylar/Al_(2)O_(3)/AlN的材料组合。仿真结果表明,在340 GHz的入射波照射下,该结构在275~405 GHz范围内反射率均低于-20 dB,将其应用于太赫兹探测器后,-3 dB带宽提升至50 GHz以上,响应度提高了3.2倍。该结构制备简单、成本低廉,为太赫兹波段的宽带减反提供了一种经济且有效的解决方案。In the terahertz band,high-resistivity silicon and sapphire are commonly used as substrates for terahertz devices owing to their low absorption,high resistivity,and low spectral dispersion.However,the high refractive index results in most of the incident terahertz waves being reflected at the interface,leading to a reduced wave transmittance and a potential Fabry-Perot resonant cavity effect,limiting the operating bandwidth and sensitivity of the terahertz device.To reduce the reflection of terahertz waves at the interface,this study proposes a three-layer anti-reflection structure.By using the transfer matrix method(TMM)in MATLAB and the finite-difference method in the time-domain(FDTD)in electromagnetic simulation,Mylar/Al_(2)O_(3)/AlN is selected as the anti-reflection structure in the terahertz range.The simulation results show that this structure can maintain a reflectivity<-20 dB in the range of 275~405 GHz.Furthermore,the terahertz detector applying this anti-reflection structure exhibits a-3 dB bandwidth enhancement of>50 GHz and a 3.2-fold increase in responsivity at 340 GHz.Additionally,the structure has a straightforward and cost-effective fabrication process,providing an economical and effective solution for broadband reflection reduction in the terahertz band.

关 键 词：太赫兹波 太赫兹探测器 干涉相消 减反膜 

分 类 号：TN386[电子电信—物理电子学] O441.4[理学—电磁学]