用于亚带隙太赫兹产生的表面等离子体增强型低温生长砷化镓/砷化铝异质结构光电导天线。

Plasmon-enhanced LT-GaAs/AlAs heterostructure photoconductive antennas for sub-bandgap terahertz generation.

作者信息

Jooshesh Afshin, Fesharaki Faezeh, Bahrami-Yekta Vahid, Mahtab Mahsa, Tiedje Thomas, Darcie Thomas E, Gordon Reuven

出版信息

Opt Express. 2017 Sep 4;25(18):22140-22148. doi: 10.1364/OE.25.022140.

DOI:10.1364/OE.25.022140

Abstract

Photocurrent generation in low-temperature-grown GaAs (LT-GaAs) has been significantly improved by growing a thin AlAs isolation layer between the LT-GaAs layer and semi-insulating (SI)-GaAs substrate. The AlAs layer allows greater arsenic incorporation into the LT-GaAs layer, prevents current diffusion into the GaAs substrate, and provides optical back-reflection that enhances below bandgap terahertz generation. Our plasmon-enhanced LT-GaAs/AlAs photoconductive antennas provide 4.5 THz bandwidth and 75 dB signal-to-noise ratio (SNR) under 50 mW of 1570 nm excitation, whereas the structure without the AlAs layer gives 3 THz bandwidth, 65 dB SNR for the same conditions.

摘要

通过在低温生长的砷化镓（LT-GaAs）层与半绝缘（SI）-砷化镓衬底之间生长一层薄的砷化铝（AlAs）隔离层，低温生长的砷化镓中的光电流产生得到了显著改善。AlAs层允许更多的砷掺入LT-GaAs层，防止电流扩散到GaAs衬底中，并提供光背反射，增强带隙以下太赫兹的产生。我们的等离子体增强LT-GaAs/AlAs光电导天线在1570nm激发功率为50mW的情况下，提供4.5THz带宽和75dB的信噪比（SNR），而没有AlAs层的结构在相同条件下给出3THz带宽、65dB SNR。