Improving unbiased terahertz photoconductive antenna based on dissimilar Schottky barriers using plasmonic mode excitation
Improving unbiased terahertz photoconductive antenna based on dissimilar Schottky barriers using plasmonic mode excitation
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DOI：
10.1016/j.ijleo.2019.162975
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发表时间：
2019-10
期刊：
影响因子：
3.1
通讯作者：
S. Ghorbani;Mohammad Bashipour;M. Kolahdouz
中科院分区：
文献类型：
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作者：
S. Ghorbani;Mohammad Bashipour;M. Kolahdouz
设计并提出了一种基于低温砷化镓（LT-GaAs）层下双金属纳米结构阵列的无偏置太赫兹（THz）光导天线（PCA）的新设计，这是太赫兹成像应用的热点。阵列的每个元件由具有不同肖特基势垒的不对称金属-半导体-金属（MSM）结构组成。仿真结果表明，用800 nm飞秒激光照射该结构可以产生与传统偏置PCA相当的太赫兹场。通过求解麦克斯韦方程，结合漂移-扩散/泊松方程，采用有限元法对主成分分析的几何参数进行优化。仿真结果表明，通过优化阵列的周期、宽度和高度，两个相邻纳米结构之间的等离子共振腔模式增强了光吸收，从而提高了瞬态光电流。得到的瞬态光电流为45 μA，比传统偏置PCA高29%。
A new design for an unbiased antennaless terahertz (THz) photoconductive antenna (PCA) using an array of bimetallic nanostructures located underneath the low temperature gallium arsenide (LT-GaAs) layer is designed and proposed which is highly under focus for THz imaging applications. Each element of array consists an asymmetric metal-semiconductor-metal (MSM) structure with dissimilar Schottky barriers. Simulation results demonstrated that by irradiating this structure using 800 nm femtosecond laser, THz field as high as a conventional biased PCA can be generated. Finite element method was used to optimize the PCA’s geometrical parameters through solving the Maxwell’s equation in combination with drift-diffusion/Poisson’s equations. According to the simulation results, by optimizing the array’s periodicity, width and height of the proposed bimetallic nanostructures, plasmonic resonant cavity mode between two adjacent nanostructures enhances the optical absorption and so, the transient photocurrent. Transient photocurrent of 45 μA was obtained that is 29% higher than the one from the conventional biased PCA.