Mao Qi, Wen Qi-Ye, Tian Wei, Wen Tian-Long, Chen Zhi, Yang Qing-Hui, Zhang Huai-Wu
Opt Lett. 2014 Oct 1;39(19):5649-52. doi: 10.1364/OL.39.005649.
We present a broadband terahertz wave modulator with improved modulation depth and switch speed by cautiously selecting the gate dielectric materials in a large-area graphene-based field-effect transistor (GFET). An ultrathin Al2O3 film (∼60 nm) is deposited by an atomic-layer-deposition technique as a high-k gate dielectric layer, which reduces the Coulomb impurity scattering and cavity effect, and thus greatly improves the modulation performance. Our modulator has achieved a modulation depth of 22% and modulation speed of 170 kHz in a frequency range from 0.4 to 1.5 THz, which is a large improvement in comparison to its predecessor of SiO2-based GFET.
我们展示了一种宽带太赫兹波调制器，通过在大面积石墨烯基场效应晶体管（GFET）中谨慎选择栅极介电材料，提高了调制深度和开关速度。采用原子层沉积技术沉积了一层超薄的Al2O3薄膜（约60nm）作为高k栅极介电层，这减少了库仑杂质散射和腔效应，从而大大提高了调制性能。我们的调制器在0.4至1.5太赫兹的频率范围内实现了22%的调制深度和170千赫兹的调制速度，与基于SiO2的GFET前身相比有了很大改进。
