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金属-半导体-金属光电探测器的光栅结构可激发表面等离子体,有效增强探测器的吸收.为深入研究器件结构对于表面等离子体的激发及共振增强的影响,本文提出了一种具有超薄有源层的硅基锗金属-半导体-金属光电探测器的设计方法.采用时域有限差分的方法详细分析了光栅周期、光栅厚度、光栅间距及有源层厚度对于表面等离子体共振增强器件性能的影响,通过仿真模拟获得了器件的最佳结构,详细地分析了各个界面激发的表面等离子体及其共振模式对于光谱吸收增强的机理.仿真结果表明,有源层锗的厚度为400 nm的超薄器件在通信波段具有较高的吸收,尤其在1550 nm波长处器件的归一化的光谱吸收率可以高达53.77%,增强因子达7.22倍.利用共振效应能够极大地提高高速器件的光电响应,为解决光电探测器响应度与响应速度之间的相互制约关系提供了有效途径.
The grating structure of metal-semiconductor-metal photodetector can excite the surface plasmon and effectively enhance the detector’s absorption.In order to further study the influence of device structure on the surface plasmon excitation and resonance enhancement, Source silicon germanium metal-semiconductor-metal photodetector design method of time-domain finite difference analysis of grating period, grating thickness, grating spacing and active layer thickness of the surface plasmon resonance enhancement device performance The best structure of the device is obtained through the simulation and the mechanism of enhanced surface plasmon resonance and its resonance mode excited by each interface is analyzed in detail.The simulation results show that the thickness of the active layer of germanium is 400 nm Thin devices have higher absorption in the communication band, and the normalized spectral absorptivity can reach 53.77% and the enhancement factor up to 7.22 times, especially at 1550 nm.The resonance effect can greatly improve the photoelectric response of high-speed devices, It provides an effective way to solve the mutual restraint relationship between photodetector responsivity and response speed.