Xiang Hengyang, Chaudhary Mahima, Tripon-Canseliet Charlotte, Chen Zhuoying
LPEM, ESPCI Paris, PSL Research University, Sorbonne Université, CNRS UMR 8213, 10 Rue Vauquelin, F-75005 Paris, France.
Nanotechnology. 2021 Aug 16;32(45). doi: 10.1088/1361-6528/ac197c.
Microwave photoconductive switches, allowing an optical control on the magnitude and phase of the microwave signals to be transmitted, are important components for many optoelectronic applications. In recent years, there are significant demands to develop photoconductive switches functional in the short-wave-infrared spectrum window (e.g. = 1.3-1.55m) but most state-of-the-art semiconductors for photoconductive switches cannot achieve this goal. In this work, we propose a novel approach, by the use of solution-processed colloidal upconversion nanocrystals deposited directly onto low-temperature-grown gallium arsenide (LT-GaAs), to achieve microwave photoconductive switches functional at = 1.55m illumination. Hybrid upconversion Er-doped NaYFnanocrystal/LT-GaAs photoconductive switch was fabricated. Under a continuous wave = 1.55m laser illumination (power density ∼ 12.9 mWm), thanks to the upconversion energy transfer from the nanocrystals, a more than 2-fold larger value in decibel was measured for the ON/OFF ratio on the hybrid nanocrystal/LT-GaAs device by comparison to the control device without upconversion nanoparticles. A maximum ON/OFF ratio reaching 20.6 dB was measured on the nanocrystal/LT-GaAs hybrid device at an input signal frequency of 20 MHz.
微波光电导开关能够对要传输的微波信号的幅度和相位进行光学控制，是许多光电子应用中的重要组件。近年来，人们对开发在短波红外光谱窗口（例如λ = 1.3 - 1.55μm）中起作用的光电导开关有很大需求，但大多数用于光电导开关的最先进半导体无法实现这一目标。在这项工作中，我们提出了一种新颖的方法，即使用直接沉积在低温生长的砷化镓（LT - GaAs）上的溶液处理胶体上转换纳米晶体，以实现对波长λ = 1.55μm光照起作用的微波光电导开关。制备了混合上转换掺铒NaYF纳米晶体/LT - GaAs光电导开关。在连续波λ = 1.55μm激光照射下（功率密度 ∼ 12.9 mW/m²），由于纳米晶体的上转换能量转移，与没有上转换纳米颗粒的对照器件相比，混合纳米晶体/LT - GaAs器件的开/关比在分贝上测量值大两倍以上。在输入信号频率为20 MHz时，在纳米晶体/LT - GaAs混合器件上测得的最大开/关比达到20.6 dB。
